diff --git a/src/simulator/gui.odin b/src/simulator/gui.odin
index 8b3b9f2..da4d655 100644
--- a/src/simulator/gui.odin
+++ b/src/simulator/gui.odin
@@ -3,9 +3,6 @@ package simulator
 import emu "../machine"
 import rl "vendor:raylib"
 
-// Globals
-run: bool
-
 // Window
 WINDOW_WIDTH  :: 1920
 WINDOW_HEIGHT :: 1080
@@ -42,21 +39,30 @@ Layout :: struct {
 }
 
 init :: proc(sim: ^Simulator) {
-	run = true
+	_sim = sim
+
+	// desktop
+	when ODIN_OS != .JS {
+		rl.SetConfigFlags({.WINDOW_RESIZABLE})
+		rl.SetTargetFPS(60)
+	}
+
+	// web
+	when ODIN_OS == .JS {
+		rl.SetConfigFlags({.VSYNC_HINT})
+	}
 
-    rl.SetConfigFlags({.WINDOW_RESIZABLE})
     rl.InitWindow(WINDOW_WIDTH, WINDOW_HEIGHT, "Octal Cookie - Chip 8 Simulator")
     rl.InitAudioDevice()
-    rl.SetTargetFPS(60)
 
 	// Load sound
     beep := rl.LoadSound("./assets/sounds/beep.wav")
-	sim.sound = beep
+	_sim.sound = beep
 
     // Load fonts
     font := rl.LoadFontEx("./assets/fonts/Inter_18pt-Regular.ttf", 18, nil, 0)
     rl.SetTextureFilter(font.texture, .BILINEAR)
-    sim.font = font
+    _sim.font = font
 
     rl.GuiLoadStyleDefault()
     rl.GuiLoadStyle("./assets/raygui_styles/genesis.rgs")
@@ -65,7 +71,9 @@ init :: proc(sim: ^Simulator) {
     rl.GuiSetStyle(.DEFAULT, i32(rl.GuiDefaultProperty.TEXT_SIZE), 18)
 }
 
-update :: proc(sim: ^Simulator) {
+update :: proc() {
+	sim := _sim
+
 	// Recalculate layout each frame based on current window size
 	// Pass these down to gui functions so they can setup their sizes?
 	screen_width  := f32(rl.GetScreenWidth())
@@ -98,7 +106,7 @@ update :: proc(sim: ^Simulator) {
 
 	// Left
 	// ------------------------------------------
-	gui_file_loader(layout.file_loader, sim)
+	when ODIN_OS != .JS { gui_file_loader(layout.file_loader, sim)}
 	gui_key_pad(layout.keypad, sim.machine.keypad, sim.font)
 
 	// Center
@@ -119,9 +127,11 @@ update :: proc(sim: ^Simulator) {
 	gui_info_box(layout.info_box, sim, screen_width, screen_height)
 
 	rl.EndDrawing()
+	free_all(context.temp_allocator)
 }
 
-shutdown :: proc(sim: ^Simulator) {
+shutdown :: proc() {
+	sim := _sim
 	rl.UnloadFont(sim.font)
 	rl.UnloadSound(sim.sound)
 	rl.CloseAudioDevice()
@@ -129,13 +139,10 @@ shutdown :: proc(sim: ^Simulator) {
 }
 
 should_run :: proc() -> bool {
-	when ODIN_OS != .JS {
-		if rl.WindowShouldClose() {
-			run = false
-		}
-	}
-
-	return run
+    when ODIN_OS != .JS {
+        return !rl.WindowShouldClose()
+    }
+    return true  // web loop is controlled by JS requestAnimationFrame
 }
 
 tick_timers :: proc(sim: ^Simulator) {
@@ -146,7 +153,8 @@ tick_timers :: proc(sim: ^Simulator) {
         sim.machine.sound_timer -= 1
         if !rl.IsSoundPlaying(beep) do rl.PlaySound(beep)
     } else {
-        rl.StopSound(beep)
+		// only stop if actually playing
+		if rl.IsSoundPlaying(beep) do rl.StopSound(beep)
     }
 }
 
diff --git a/src/simulator/simulator.odin b/src/simulator/simulator.odin
index 3c3a69e..1cd8bb7 100644
--- a/src/simulator/simulator.odin
+++ b/src/simulator/simulator.odin
@@ -3,6 +3,9 @@ package simulator
 import emu "../machine"
 import rl "vendor:raylib"
 
+@(private="package")
+_sim: ^Simulator
+
 // Embed roms
 roms := #load_directory("../roms")
 
@@ -43,19 +46,3 @@ Simulator :: struct {
 	disasm_count:	   int,
 	disasm_scroll:     rl.Vector2,
 }
-
-// Requires an initilized emulatore System Struct
-/*
-run_simulator :: proc(s: ^emu.System) {
-	sim := Simulator {
-		machine = s,
-		rom_loaded = false,
-		paused = true,
-		step = false,
-		cpu_hz = 700,
-		disasm_follow = true,
-	}
-
-	run_gui(&sim)
-}
-*/