diff --git a/artifacts/config_files/Perks.ini b/artifacts/config_files/Perks.ini
index 37e82fc1..22232654 100644
--- a/artifacts/config_files/Perks.ini
+++ b/artifacts/config_files/Perks.ini
@@ -28,7 +28,7 @@ WeaponHandlingBonus=3
 
 ;##############################################################################
 [Perks]
-;Set to 1 to enable the modifications to perks
+;Set to 1 to enable modifications to perks
 Enable=0
 
 ;Name=The name of the perk (max 63 characters)
@@ -125,7 +125,7 @@ Skill5Mod=0
 
 ;##############################################################################
 [Traits]
-;Set to 1 to enable the modifications to traits
+;Set to 1 to enable modifications to traits
 Enable=0
 
 ;This is a modification to trait 0
diff --git a/sfall/Modules/HookScripts.cpp b/sfall/Modules/HookScripts.cpp
index 2b9b09bc..ccafafd9 100644
--- a/sfall/Modules/HookScripts.cpp
+++ b/sfall/Modules/HookScripts.cpp
@@ -141,11 +141,11 @@ DWORD _stdcall GetHSArg() {
 	return (cArg == argCount) ? 0 : args[cArg++];
 }
 
-void _stdcall SetHSArg(DWORD id, DWORD value) {
+void SetHSArg(DWORD id, DWORD value) {
 	if (id < argCount) args[id] = value;
 }
 
-DWORD* _stdcall GetHSArgs() {
+DWORD* GetHSArgs() {
 	return args;
 }
 
diff --git a/sfall/Modules/HookScripts.h b/sfall/Modules/HookScripts.h
index 0a81b86b..75c0f8f1 100644
--- a/sfall/Modules/HookScripts.h
+++ b/sfall/Modules/HookScripts.h
@@ -88,8 +88,8 @@ public:
 
 DWORD _stdcall GetHSArgCount();
 DWORD _stdcall GetHSArg();
-DWORD* _stdcall GetHSArgs();
-void _stdcall SetHSArg(DWORD id, DWORD value);
+DWORD* GetHSArgs();
+void SetHSArg(DWORD id, DWORD value);
 void _stdcall SetHSReturn(DWORD d);
 
 // register hook by proc num (special values: -1 - use default (start) procedure, 0 - unregister)
diff --git a/sfall/Modules/Perks.cpp b/sfall/Modules/Perks.cpp
index af0573fb..a9d22ef0 100644
--- a/sfall/Modules/Perks.cpp
+++ b/sfall/Modules/Perks.cpp
@@ -29,6 +29,8 @@ namespace sfall
 {
 using namespace fo;
 
+long Perks::PerkLevelMod = 0;
+
 constexpr int maxNameLen = 64;   // don't change size
 constexpr int maxDescLen = 512;  // don't change size
 static const int descLen = 256;  // maximum text length for interface
@@ -1291,7 +1293,7 @@ void PerksReset() {
 
 	// Reset some settable game values back to the defaults
 	// Perk level mod
-	SafeWrite32(0x496880, 0x019078);
+	Perks::PerkLevelMod = 0;
 	// Pyromaniac bonus
 	SafeWrite8(0x424AB6, 5);
 	// Swift Learner bonus
diff --git a/sfall/Modules/Perks.h b/sfall/Modules/Perks.h
index 5b448286..dab65212 100644
--- a/sfall/Modules/Perks.h
+++ b/sfall/Modules/Perks.h
@@ -39,6 +39,8 @@ public:
 	static DWORD HasFakeTrait(const char* name);
 	static DWORD HasFakePerkOwner(const char* name, long objId);
 	static DWORD HasFakeTraitOwner(const char* name, long objId);
+
+	static long PerkLevelMod;
 };
 
 void PerksEnterCharScreen();
diff --git a/sfall/Modules/Scripting/Handlers/Core.cpp b/sfall/Modules/Scripting/Handlers/Core.cpp
index b086ab59..ea0a17e1 100644
--- a/sfall/Modules/Scripting/Handlers/Core.cpp
+++ b/sfall/Modules/Scripting/Handlers/Core.cpp
@@ -35,13 +35,11 @@ namespace script
 void __declspec(naked) op_set_global_script_repeat() {
 	__asm {
 		push ecx;
-		push edx;
 		mov  ecx, eax;
 		_GET_ARG_INT(end);
 		mov  edx, eax;              // frames
 		call SetGlobalScriptRepeat; // ecx - script
 end:
-		pop edx;
 		pop ecx;
 		retn;
 	}
@@ -50,13 +48,11 @@ end:
 void __declspec(naked) op_set_global_script_type() {
 	__asm {
 		push ecx;
-		push edx;
 		mov  ecx, eax;
 		_GET_ARG_INT(end);
 		mov  edx, eax;            // type
 		call SetGlobalScriptType; // ecx - script
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -65,10 +61,8 @@ end:
 void __declspec(naked) op_available_global_script_types() {
 	__asm {
 		push ecx;
-		push edx;
 		mov  edx, availableGlobalScriptTypes;
 		_RET_VAL_INT(ecx);
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -114,79 +108,37 @@ void sf_get_sfall_global_float(OpcodeContext& ctx) {
 void __declspec(naked) op_get_sfall_arg() {
 	__asm {
 		push ecx;
-		push edx;
 		push eax;
 		call GetHSArg;
 		mov  edx, eax;
 		pop  eax;
 		_RET_VAL_INT(ecx);
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
 }
 
-static DWORD _stdcall GetSfallArgs() {
+void sf_get_sfall_args(OpcodeContext& ctx) {
 	DWORD argCount = GetHSArgCount();
 	DWORD id = TempArray(argCount, 0);
 	DWORD* args = GetHSArgs();
 	for (DWORD i = 0; i < argCount; i++) {
 		arrays[id].val[i].set(*(long*)&args[i]);
 	}
-	return id;
+	ctx.setReturn(id);
 }
 
-void __declspec(naked) op_get_sfall_args() { // rewrite to c++
-	__asm {
-		push ecx;
-		push edx;
-		push eax;
-		call GetSfallArgs;
-		mov  edx, eax;
-		pop  eax;
-		_RET_VAL_INT(ecx);
-		pop  edx;
-		pop  ecx;
-		retn;
-	}
-}
-
-void __declspec(naked) op_set_sfall_arg() {
-	__asm {
-		pushad;
-		mov ecx, eax;
-		call fo::funcoffs::interpretPopShort_;
-		mov edi, eax;
-		mov eax, ecx;
-		call fo::funcoffs::interpretPopLong_;
-		mov edx, eax;
-		mov eax, ecx;
-		call fo::funcoffs::interpretPopShort_;
-		mov esi, eax;
-		mov eax, ecx;
-		call fo::funcoffs::interpretPopLong_;
-		cmp di, VAR_TYPE_INT;
-		jnz end;
-		cmp si, VAR_TYPE_INT;
-		jnz end;
-		push edx;
-		push eax;
-		call SetHSArg;
-end:
-		popad;
-		retn;
-	}
+void sf_set_sfall_arg(OpcodeContext& ctx) {
+	SetHSArg(ctx.arg(0).rawValue(), ctx.arg(1).rawValue());
 }
 
 void __declspec(naked) op_set_sfall_return() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		call SetHSReturn;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -194,26 +146,22 @@ end:
 
 void __declspec(naked) op_init_hook() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, initingHookScripts;
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
 
-void __declspec(naked) op_set_self() { // rewrite to c++
+void __declspec(naked) op_set_self() {
 	__asm {
 		push ecx;
-		push edx;
 		mov  ecx, eax;
 		_GET_ARG_INT(end);
 		mov  edx, eax;      // object
 		call SetSelfObject; // ecx - script
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
diff --git a/sfall/Modules/Scripting/Handlers/Core.h b/sfall/Modules/Scripting/Handlers/Core.h
index eb1ead6e..f3d76a91 100644
--- a/sfall/Modules/Scripting/Handlers/Core.h
+++ b/sfall/Modules/Scripting/Handlers/Core.h
@@ -41,9 +41,9 @@ void sf_get_sfall_global_float(OpcodeContext&);
 
 void __declspec() op_get_sfall_arg();
 
-void __declspec() op_get_sfall_args();
+void sf_get_sfall_args(OpcodeContext&);
 
-void __declspec() op_set_sfall_arg();
+void sf_set_sfall_arg(OpcodeContext&);
 
 void __declspec() op_set_sfall_return();
 
diff --git a/sfall/Modules/Scripting/Handlers/Graphics.cpp b/sfall/Modules/Scripting/Handlers/Graphics.cpp
index 39d7d2e5..18b4c9d5 100644
--- a/sfall/Modules/Scripting/Handlers/Graphics.cpp
+++ b/sfall/Modules/Scripting/Handlers/Graphics.cpp
@@ -32,14 +32,12 @@ namespace script
 
 void __declspec(naked) op_graphics_funcs_available() {
 	__asm {
-		push edx;
 		push ecx;
 		cmp  Graphics::mode, 3;
 		seta dl;
 		and  edx, 0xFF;
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -86,12 +84,10 @@ result:
 void __declspec(naked) op_free_shader() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		call FreeShader;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -100,12 +96,10 @@ end:
 void __declspec(naked) op_activate_shader() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		call ActivateShader;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -114,12 +108,10 @@ end:
 void __declspec(naked) op_deactivate_shader() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		call DeactivateShader;
 end:
-		pop edx;
 		pop ecx;
 		retn;
 	}
@@ -414,13 +406,11 @@ end:
 void __declspec(naked) op_get_shader_version() {
 	__asm {
 		push ecx;
-		push edx;
 		push eax;
 		call GetShaderVersion;
 		mov  edx, eax;
 		pop  eax;
 		_RET_VAL_INT(ecx);
-		pop edx;
 		pop ecx;
 		retn;
 	}
@@ -464,12 +454,10 @@ end:
 void __declspec(naked) op_force_graphics_refresh() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		call ForceGraphicsRefresh;
 end:
-		pop edx;
 		pop ecx;
 		retn;
 	}
diff --git a/sfall/Modules/Scripting/Handlers/Interface.cpp b/sfall/Modules/Scripting/Handlers/Interface.cpp
index f8ef13e7..8a778538 100644
--- a/sfall/Modules/Scripting/Handlers/Interface.cpp
+++ b/sfall/Modules/Scripting/Handlers/Interface.cpp
@@ -35,10 +35,8 @@ namespace script
 void __declspec(naked) op_input_funcs_available() {
 	__asm {
 		push ecx;
-		push edx;
 		mov  edx, 1; // They're always available from 2.9 on
 		_RET_VAL_INT(ecx);
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -51,7 +49,6 @@ void sf_key_pressed(OpcodeContext& ctx) {
 void __declspec(naked) op_tap_key() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		test eax, eax;
 		jl   end;
@@ -60,7 +57,6 @@ void __declspec(naked) op_tap_key() {
 		push eax;
 		call TapKey;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -68,26 +64,22 @@ end:
 
 void __declspec(naked) op_get_mouse_x() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, ds:[FO_VAR_mouse_x_];
 		add  edx, ds:[FO_VAR_mouse_hotx];
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
 
 void __declspec(naked) op_get_mouse_y() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, ds:[FO_VAR_mouse_y_];
 		add  edx, ds:[FO_VAR_mouse_hoty];
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -103,40 +95,34 @@ void sf_get_mouse_buttons(OpcodeContext& ctx) {
 
 void __declspec(naked) op_get_window_under_mouse() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, ds:[FO_VAR_last_button_winID];
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
 
 void __declspec(naked) op_get_screen_width() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, ds:[FO_VAR_scr_size + 8]; // _scr_size.offx
 		sub  edx, ds:[FO_VAR_scr_size];     // _scr_size.x
 		inc  edx;
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
 
 void __declspec(naked) op_get_screen_height() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, ds:[FO_VAR_scr_size + 12]; // _scr_size.offy
 		sub  edx, ds:[FO_VAR_scr_size + 4];  // _scr_size.y
 		inc  edx;
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -165,24 +151,20 @@ void sf_create_message_window(OpcodeContext &ctx) {
 
 void __declspec(naked) op_get_viewport_x() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, ds:[FO_VAR_wmWorldOffsetX];
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
 
 void __declspec(naked) op_get_viewport_y() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, ds:[FO_VAR_wmWorldOffsetY];
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -190,11 +172,9 @@ void __declspec(naked) op_get_viewport_y() {
 void __declspec(naked) op_set_viewport_x() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		mov  ds:[FO_VAR_wmWorldOffsetX], eax;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -203,11 +183,9 @@ end:
 void __declspec(naked) op_set_viewport_y() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		mov  ds:[FO_VAR_wmWorldOffsetY], eax;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -323,19 +301,23 @@ void sf_set_iface_tag_text(OpcodeContext& ctx) {
 
 void sf_inventory_redraw(OpcodeContext& ctx) {
 	int mode;
-	DWORD loopFlag = GetLoopFlags();
-	if (loopFlag & INVENTORY) {
-		mode = 0;
-	} else if (loopFlag & INTFACEUSE) {
-		mode = 1;
-	} else if (loopFlag & INTFACELOOT) {
-		mode = 2;
-	} else if (loopFlag & BARTER) {
-		mode = 3;
-	} else {
-		return;
+	DWORD loopFlag = GetLoopFlags() & (INVENTORY | INTFACEUSE | INTFACELOOT | BARTER);
+	switch (loopFlag) {
+		case INVENTORY:
+			mode = 0;
+			break;
+		case INTFACEUSE:
+			mode = 1;
+			break;
+		case INTFACELOOT:
+			mode = 2;
+			break;
+		case BARTER:
+			mode = 3;
+			break;
+		default:
+			return;
 	}
-
 	if (!ctx.arg(0).asBool()) {
 		fo::var::stack_offset[fo::var::curr_stack] = 0;
 		fo::func::display_inventory(0, -1, mode);
diff --git a/sfall/Modules/Scripting/Handlers/Misc.cpp b/sfall/Modules/Scripting/Handlers/Misc.cpp
index ea1248c8..af73e0e0 100644
--- a/sfall/Modules/Scripting/Handlers/Misc.cpp
+++ b/sfall/Modules/Scripting/Handlers/Misc.cpp
@@ -289,8 +289,6 @@ void sf_set_object_knockback(OpcodeContext& ctx) {
 	case 0x197:
 		mode = 2;
 		break;
-	default:
-		break;
 	}
 	fo::GameObject* object = ctx.arg(0).asObject();
 	if (mode) {
@@ -316,8 +314,6 @@ void sf_remove_object_knockback(OpcodeContext& ctx) {
 	case 0x19a:
 		mode = 2;
 		break;
-	default:
-		break;
 	}
 	KnockbackRemoveMod(ctx.arg(0).asObject(), mode);
 }
@@ -390,12 +386,10 @@ end:
 
 void __declspec(naked) op_active_hand() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, dword ptr ds:[FO_VAR_itemCurrentItem];
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -409,12 +403,10 @@ void __declspec(naked) op_toggle_active_hand() {
 
 void __declspec(naked) op_eax_available() {
 	__asm {
-		push edx;
 		push ecx;
 		xor  edx, edx
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -589,13 +581,11 @@ void sf_get_ini_string(OpcodeContext& ctx) {
 void __declspec(naked) op_get_uptime() {
 	__asm {
 		push ecx;
-		push edx;
 		push eax;
 		call GetTickCount;
 		mov  edx, eax;
 		pop  eax;
 		_RET_VAL_INT(ecx);
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -604,11 +594,9 @@ void __declspec(naked) op_get_uptime() {
 void __declspec(naked) op_set_car_current_town() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		mov  ds:[FO_VAR_carCurrentArea], eax;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -617,13 +605,11 @@ end:
 void __declspec(naked) op_set_hp_per_level_mod() { // rewrite to c++
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax; // allowed -/+127
 		push 0x4AFBC1;
 		call SafeWrite8;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -736,11 +722,9 @@ void sf_reset_critical_table(OpcodeContext& ctx) {
 void __declspec(naked) op_set_unspent_ap_bonus() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
-		mov  standardApAcBonus, eax;
+		mov  Stats::standardApAcBonus, eax;
 end:
-		pop edx;
 		pop ecx;
 		retn;
 	}
@@ -748,12 +732,10 @@ end:
 
 void __declspec(naked) op_get_unspent_ap_bonus() {
 	__asm {
-		push edx;
 		push ecx;
-		mov  edx, standardApAcBonus;
+		mov  edx, Stats::standardApAcBonus;
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -761,11 +743,9 @@ void __declspec(naked) op_get_unspent_ap_bonus() {
 void __declspec(naked) op_set_unspent_ap_perk_bonus() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
-		mov  extraApAcBonus, eax;
+		mov  Stats::extraApAcBonus, eax;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -773,12 +753,10 @@ end:
 
 void __declspec(naked) op_get_unspent_ap_perk_bonus() {
 	__asm {
-		push edx;
 		push ecx;
-		mov  edx, extraApAcBonus;
+		mov  edx, Stats::extraApAcBonus;
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -835,12 +813,10 @@ void __declspec(naked) op_nb_create_char() {
 void __declspec(naked) op_hero_select_win() { // for opening the appearance selection window
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(fail);
 		push eax;
 		call HeroSelectWindow;
 fail:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -849,12 +825,10 @@ fail:
 void __declspec(naked) op_set_hero_style() { // for setting the hero style/appearance takes an 1 int
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(fail);
 		push eax;
 		call SetHeroStyle;
 fail:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -863,12 +837,10 @@ fail:
 void __declspec(naked) op_set_hero_race() { // for setting the hero race takes an 1 int
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(fail);
 		push eax;
 		call SetHeroRace;
 fail:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -876,12 +848,10 @@ fail:
 
 void __declspec(naked) op_get_light_level() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, ds:[FO_VAR_ambient_light];
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -889,9 +859,7 @@ void __declspec(naked) op_get_light_level() {
 void __declspec(naked) op_refresh_pc_art() {
 	__asm {
 		push ecx;
-		push edx;
 		call RefreshPCArt;
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -945,12 +913,10 @@ end:
 void __declspec(naked) op_stop_sfall_sound() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		call StopSfallSound;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -992,12 +958,10 @@ end:
 
 void __declspec(naked) op_modified_ini() {
 	__asm {
-		push edx;
 		push ecx;
 		mov edx, modifiedIni;
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -1005,12 +969,10 @@ void __declspec(naked) op_modified_ini() {
 void __declspec(naked) op_force_aimed_shots() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		call ForceAimedShots;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -1019,12 +981,10 @@ end:
 void __declspec(naked) op_disable_aimed_shots() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		call DisableAimedShots;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -1033,7 +993,6 @@ end:
 void __declspec(naked) op_mark_movie_played() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		test eax, eax;
 		jl   end;
@@ -1041,7 +1000,6 @@ void __declspec(naked) op_mark_movie_played() {
 		jge  end;
 		mov  byte ptr ds:[eax + FO_VAR_gmovie_played_list], 1;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -1104,12 +1062,10 @@ end:
 void __declspec(naked) op_block_combat() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		call AIBlockCombat;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -1145,12 +1101,10 @@ void __declspec(naked) op_tile_under_cursor() {
 
 void __declspec(naked) op_gdialog_get_barter_mod() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, dword ptr ds:[FO_VAR_gdBarterMod];
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -1158,12 +1112,10 @@ void __declspec(naked) op_gdialog_get_barter_mod() {
 void __declspec(naked) op_set_inven_ap_cost() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		call SetInvenApCost;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
diff --git a/sfall/Modules/Scripting/Handlers/Perks.cpp b/sfall/Modules/Scripting/Handlers/Perks.cpp
index a470bfa8..1a3c5f30 100644
--- a/sfall/Modules/Scripting/Handlers/Perks.cpp
+++ b/sfall/Modules/Scripting/Handlers/Perks.cpp
@@ -30,12 +30,10 @@ namespace script
 
 void __declspec(naked) op_get_perk_owed() {
 	__asm {
-		push edx;
 		push ecx;
 		movzx edx, byte ptr ds:[FO_VAR_free_perk];
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -43,14 +41,12 @@ void __declspec(naked) op_get_perk_owed() {
 void __declspec(naked) op_set_perk_owed() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		and  eax, 0xFF;
 		cmp  eax, 250;
 		jg   end;
 		mov  byte ptr ds:[FO_VAR_free_perk], al;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -59,12 +55,10 @@ end:
 void __declspec(naked) op_set_perk_freq() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		call SetPerkFreq;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -309,12 +303,10 @@ void sf_has_fake_trait_npc(OpcodeContext& ctx) {
 void __declspec(naked) op_perk_add_mode() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		call AddPerkMode;
 end:
-		pop edx;
 		pop ecx;
 		retn;
 	}
@@ -347,13 +339,11 @@ next:
 void __declspec(naked) op_set_pyromaniac_mod() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		push 0x424AB6;
 		call SafeWrite8;
 end:
-		pop edx;
 		pop ecx;
 		retn;
 	}
@@ -371,13 +361,45 @@ void __declspec(naked) op_apply_heaveho_fix() {
 void __declspec(naked) op_set_swiftlearner_mod() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		push eax;
 		push 0x4AFAE2;
 		call SafeWrite32;
 end:
-		pop  edx;
+		pop  ecx;
+		retn;
+	}
+}
+
+static void __declspec(naked) perk_can_add_hook() {
+	__asm {
+		call fo::funcoffs::stat_pc_get_;
+		add  eax, Perks::PerkLevelMod;
+		js   jneg; // level < 0
+		retn;
+jneg:
+		xor  eax, eax;
+		retn;
+	}
+}
+
+static void __fastcall SetPerkLevelMod(long mod) {
+	static bool perkLevelModPatch = false;
+	if (mod < -25 || mod > 25) return;
+	Perks::PerkLevelMod = mod;
+
+	if (perkLevelModPatch) return;
+	perkLevelModPatch = true;
+	HookCall(0x49687F, perk_can_add_hook);
+}
+
+void __declspec(naked) op_set_perk_level_mod() {
+	__asm {
+		push ecx;
+		_GET_ARG_INT(end);
+		mov  ecx, eax;
+		call SetPerkLevelMod;
+end:
 		pop  ecx;
 		retn;
 	}
diff --git a/sfall/Modules/Scripting/Handlers/Perks.h b/sfall/Modules/Scripting/Handlers/Perks.h
index 1e2d6c84..1a781bb4 100644
--- a/sfall/Modules/Scripting/Handlers/Perks.h
+++ b/sfall/Modules/Scripting/Handlers/Perks.h
@@ -75,5 +75,7 @@ void __declspec() op_apply_heaveho_fix();
 
 void __declspec() op_set_swiftlearner_mod();
 
+void __declspec() op_set_perk_level_mod();
+
 }
 }
diff --git a/sfall/Modules/Scripting/Handlers/Stats.cpp b/sfall/Modules/Scripting/Handlers/Stats.cpp
index 9d3f4402..b4db3776 100644
--- a/sfall/Modules/Scripting/Handlers/Stats.cpp
+++ b/sfall/Modules/Scripting/Handlers/Stats.cpp
@@ -237,13 +237,11 @@ end:
 void __declspec(naked) op_set_available_skill_points() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		mov  edx, eax;
 		xor  eax, eax;
 		call fo::funcoffs::stat_pc_set_;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -251,12 +249,10 @@ end:
 
 void __declspec(naked) op_get_available_skill_points() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, dword ptr ds:[FO_VAR_curr_pc_stat];
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
@@ -264,7 +260,6 @@ void __declspec(naked) op_get_available_skill_points() {
 void __declspec(naked) op_mod_skill_points_per_level() {
 	__asm {
 		push ecx;
-		push edx;
 		_GET_ARG_INT(end);
 		cmp  eax, 100;
 		jg   end;
@@ -275,7 +270,6 @@ void __declspec(naked) op_mod_skill_points_per_level() {
 		push 0x43C27A;
 		call SafeWrite8;
 end:
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -876,88 +870,29 @@ end:
 	}
 }
 
-static float xpmod;
-static DWORD xptmp;
-static void __declspec(naked) SetXpMod3() {
+static DWORD xpTemp;
+static void __declspec(naked) statPCAddExperienceCheckPMs_hack() {
 	__asm {
-		push ebx;
-		push ecx;
-		push esi;
-		push edi;
-		push ebp;
-		mov  xptmp, eax;
-		fild xptmp;
-		fmul xpmod;
-		fistp xptmp;
-		mov  eax, xptmp;
-		push 0x4AFABD;
-		retn;
+		mov  ebp, [esp];  // return addr
+		mov  xpTemp, eax; // experience
+		fild xpTemp;
+		fmul Stats::experienceMod;
+		fistp xpTemp;
+		mov  eax, xpTemp;
+		sub  esp, 0xC; // instead of 0x10
+		mov  edi, eax;
+		jmp  ebp;
 	}
 }
 
-static void _stdcall SetXpMod2(DWORD percent) {
-	MakeJump(0x4AFAB8, SetXpMod3);
-	xpmod = (float)percent / 100.0f;
-}
+void sf_set_xp_mod(OpcodeContext& ctx) {
+	static bool xpModPatch = false;
+	DWORD percent = ctx.arg(0).rawValue() & 0xFFFF;
+	Stats::experienceMod = (float)percent / 100.0f;
 
-static int PerkLevelMod;
-static void __declspec(naked) SetPerkLevelMod3() {
-	__asm {
-		push ebx;
-		call fo::funcoffs::stat_pc_get_;
-		pop ebx;
-		add eax, PerkLevelMod;
-		cmp eax, 0;
-		jge end;
-		xor eax, eax;
-end:
-		retn;
-	}
-}
-
-static void _stdcall SetPerkLevelMod2(int mod) {
-	if (mod < -25 || mod > 25) return;
-	PerkLevelMod = mod;
-	HookCall(0x49687F, &SetPerkLevelMod3);
-}
-
-void __declspec(naked) op_set_xp_mod() {
-	__asm {
-		push ebx;
-		push ecx;
-		push edx;
-		push edi;
-		mov ecx, eax;
-		call fo::funcoffs::interpretPopShort_;
-		mov edx, eax;
-		mov eax, ecx;
-		call fo::funcoffs::interpretPopLong_;
-		cmp dx, VAR_TYPE_INT;
-		jnz end;
-		and eax, 0xFFFF;
-		push eax;
-		call SetXpMod2;
-end:
-		pop edi;
-		pop edx;
-		pop ecx;
-		pop ebx;
-		retn;
-	}
-}
-
-void __declspec(naked) op_set_perk_level_mod() {
-	__asm {
-		push ecx;
-		push edx;
-		_GET_ARG_INT(end);
-		push eax;
-		call SetPerkLevelMod2;
-end:
-		pop edx;
-		pop ecx;
-		retn;
-	}
+	if (xpModPatch) return;
+	xpModPatch = true;
+	MakeCall(0x4AFABD, statPCAddExperienceCheckPMs_hack);
 }
 
 }
diff --git a/sfall/Modules/Scripting/Handlers/Stats.h b/sfall/Modules/Scripting/Handlers/Stats.h
index df8062a9..90b6f608 100644
--- a/sfall/Modules/Scripting/Handlers/Stats.h
+++ b/sfall/Modules/Scripting/Handlers/Stats.h
@@ -84,9 +84,7 @@ void __declspec() op_set_npc_stat_max();
 
 void __declspec() op_set_npc_stat_min();
 
-void __declspec() op_set_xp_mod();
-
-void __declspec() op_set_perk_level_mod();
+void sf_set_xp_mod(OpcodeContext&);
 
 }
 }
diff --git a/sfall/Modules/Scripting/Handlers/Worldmap.cpp b/sfall/Modules/Scripting/Handlers/Worldmap.cpp
index 50bc6bd7..7afb68fd 100644
--- a/sfall/Modules/Scripting/Handlers/Worldmap.cpp
+++ b/sfall/Modules/Scripting/Handlers/Worldmap.cpp
@@ -89,13 +89,11 @@ void sf_force_encounter(OpcodeContext& cxt) {
 void __declspec(naked) op_in_world_map() {
 	__asm {
 		push ecx;
-		push edx;
 		push eax;
 		call InWorldMap;
 		mov  edx, eax;
 		pop  eax;
 		_RET_VAL_INT(ecx);
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -104,13 +102,11 @@ void __declspec(naked) op_in_world_map() {
 void __declspec(naked) op_get_game_mode() {
 	__asm {
 		push ecx;
-		push edx;
 		push eax;
 		call GetLoopFlags;
 		mov  edx, eax;
 		pop  eax;
 		_RET_VAL_INT(ecx);
-		pop  edx;
 		pop  ecx;
 		retn;
 	}
@@ -118,24 +114,20 @@ void __declspec(naked) op_get_game_mode() {
 
 void __declspec(naked) op_get_world_map_x_pos() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, ds:[FO_VAR_world_xpos];
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
 
 void __declspec(naked) op_get_world_map_y_pos() {
 	__asm {
-		push edx;
 		push ecx;
 		mov  edx, ds:[FO_VAR_world_ypos];
 		_RET_VAL_INT(ecx);
 		pop  ecx;
-		pop  edx;
 		retn;
 	}
 }
diff --git a/sfall/Modules/Scripting/Opcodes.cpp b/sfall/Modules/Scripting/Opcodes.cpp
index edb15565..e4bf2fa4 100644
--- a/sfall/Modules/Scripting/Opcodes.cpp
+++ b/sfall/Modules/Scripting/Opcodes.cpp
@@ -86,6 +86,7 @@ static SfallOpcodeInfo opcodeInfoArray[] = {
 	{0x19e, "get_sfall_global_int",      sf_get_sfall_global_int,      1, true,  {ARG_INTSTR}},
 	{0x19f, "get_sfall_global_float",    sf_get_sfall_global_float,    1, true,  {ARG_INTSTR}},
 	{0x1a5, "inc_npc_level",             sf_inc_npc_level,             1, false, {ARG_INTSTR}},
+	{0x1aa, "set_xp_mod",                sf_set_xp_mod,                1, false, {ARG_INT}},
 	{0x1ac, "get_ini_setting",           sf_get_ini_setting,           1, true,  {ARG_STRING}},
 
 	{0x1bb, "set_fake_perk",             sf_set_fake_perk,             4, false, {ARG_STRING, ARG_INT, ARG_INT, ARG_STRING}},
@@ -159,6 +160,8 @@ static SfallOpcodeInfo opcodeInfoArray[] = {
 	{0x237, "atoi",                      sf_atoi,                      1, true,  {ARG_STRING}},
 	{0x238, "atof",                      sf_atof,                      1, true,  {ARG_STRING}},
 	{0x239, "scan_array",                sf_scan_array,                2, true,  {ARG_OBJECT, ARG_ANY}},
+	{0x23c, "get_sfall_args",            sf_get_sfall_args,            0, true},
+	{0x23d, "set_sfall_arg",             sf_set_sfall_arg,             2, false, {ARG_INT, ARG_INT}},
 	{0x241, "get_npc_level",             sf_get_npc_level,             1, true,  {ARG_INTSTR}},
 
 	{0x24e, "substr",                    sf_substr,                    3, true,  {ARG_STRING, ARG_INT, ARG_INT}},
@@ -327,7 +330,6 @@ void InitNewOpcodes() {
 	opcodes[0x1a7] = op_get_viewport_y;
 	opcodes[0x1a8] = op_set_viewport_x;
 	opcodes[0x1a9] = op_set_viewport_y;
-	opcodes[0x1aa] = op_set_xp_mod;
 	opcodes[0x1ab] = op_set_perk_level_mod;
 	opcodes[0x1ad] = op_get_shader_version;
 	opcodes[0x1ae] = op_set_shader_mode;
@@ -394,8 +396,6 @@ void InitNewOpcodes() {
 
 	opcodes[0x23a] = op_get_tile_fid;
 	opcodes[0x23b] = op_modified_ini;
-	opcodes[0x23c] = op_get_sfall_args;
-	opcodes[0x23d] = op_set_sfall_arg;
 	opcodes[0x23e] = op_force_aimed_shots;
 	opcodes[0x23f] = op_disable_aimed_shots;
 	opcodes[0x240] = op_mark_movie_played;
diff --git a/sfall/Modules/Stats.cpp b/sfall/Modules/Stats.cpp
index 0602ac20..f2ab8b23 100644
--- a/sfall/Modules/Stats.cpp
+++ b/sfall/Modules/Stats.cpp
@@ -16,9 +16,6 @@
  *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <math.h>
-#include <stdio.h>
-
 #include "..\main.h"
 #include "..\FalloutEngine\Fallout2.h"
 #include "CritterStats.h"
@@ -36,6 +33,10 @@ static DWORD statMinimumsNPC[fo::STAT_max_stat];
 
 static DWORD xpTable[99];
 
+float Stats::experienceMod = 1.0f; // set_xp_mod func
+DWORD Stats::standardApAcBonus = 4;
+DWORD Stats::extraApAcBonus = 4;
+
 static struct StatFormula {
 	long base;
 	long min;
@@ -43,9 +44,6 @@ static struct StatFormula {
 	double multi[fo::STAT_lu + 1];
 } statFormulas[fo::STAT_max_derived + 1] = {0};
 
-DWORD standardApAcBonus = 4;
-DWORD extraApAcBonus = 4;
-
 static fo::GameObject* cCritter;
 
 static const DWORD StatLevelHack_Ret = 0x4AEF52;
@@ -136,12 +134,12 @@ static void __declspec(naked) CalcApToAcBonus() {
 		mov  edx, PERK_hth_evade_perk;
 		mov  eax, dword ptr ds:[FO_VAR_obj_dude];
 		call fo::funcoffs::perk_level_;
-		imul eax, extraApAcBonus;        // bonus = perkLvl * extraApBonus
-		imul eax, edi;                   // perkBonus = bonus * curAP
+		imul eax, Stats::extraApAcBonus;    // bonus = perkLvl * extraApBonus
+		imul eax, edi;                      // perkBonus = bonus * curAP
 standard:
-		imul edi, standardApAcBonus;     // stdBonus = curAP * standardApBonus
-		add  eax, edi;                   // bonus = perkBonus + stdBonus
-		shr  eax, 2;                     // acBonus = bonus / 4
+		imul edi, Stats::standardApAcBonus; // stdBonus = curAP * standardApBonus
+		add  eax, edi;                      // bonus = perkBonus + stdBonus
+		shr  eax, 2;                        // acBonus = bonus / 4
 end:
 		retn;
 	}
@@ -212,13 +210,11 @@ allow:
 	}
 }
 
-void StatsReset() {
+static void StatsReset() {
 	for (int i = 0; i < fo::STAT_max_stat; i++) {
 		statMaximumsPC[i] = statMaximumsNPC[i] = fo::var::stat_data[i].maxValue;
 		statMinimumsPC[i] = statMinimumsNPC[i] = fo::var::stat_data[i].minValue;
 	}
-	standardApAcBonus = 4;
-	extraApAcBonus = 4;
 }
 
 void Stats::init() {
@@ -228,13 +224,14 @@ void Stats::init() {
 
 	LoadGameHook::OnGameReset() += []() {
 		StatsReset();
-		//Reset some settable game values back to the defaults
-		//xp mod
-		SafeWrite8(0x4AFAB8, 0x53);
-		SafeWrite32(0x4AFAB9, 0x55575651);
-		//HP bonus
+		// Reset some settable game values back to the defaults
+		standardApAcBonus = 4;
+		extraApAcBonus = 4;
+		// XP mod set to 100%
+		experienceMod = 1.0f;
+		// HP bonus
 		SafeWrite8(0x4AFBC1, 2);
-		//skill points per level mod
+		// Skill points per level mod
 		SafeWrite8(0x43C27A, 5);
 	};
 
diff --git a/sfall/Modules/Stats.h b/sfall/Modules/Stats.h
index 3eec3b23..13c009e8 100644
--- a/sfall/Modules/Stats.h
+++ b/sfall/Modules/Stats.h
@@ -27,13 +27,15 @@ class Stats : public Module {
 public:
 	const char* name() { return "Stats"; }
 	void init();
+
+	static float experienceMod;
+	static DWORD standardApAcBonus;
+	static DWORD extraApAcBonus;
 };
 
 void _stdcall SetPCStatMax(int stat, int i);
 void _stdcall SetPCStatMin(int stat, int i);
 void _stdcall SetNPCStatMax(int stat, int i);
 void _stdcall SetNPCStatMin(int stat, int i);
-extern DWORD standardApAcBonus;
-extern DWORD extraApAcBonus;
 
 }