diff --git a/flixel/FlxSprite.hx b/flixel/FlxSprite.hx
index 332c85c63c..8095317a0a 100644
--- a/flixel/FlxSprite.hx
+++ b/flixel/FlxSprite.hx
@@ -28,7 +28,7 @@ import flixel.util.FlxColor;
 import flixel.util.FlxDestroyUtil;
 import openfl.display.Tilesheet;
 
-@:bitmap("assets/images/logo/default.png")
+@:keep @:bitmap("assets/images/logo/default.png")
 private class GraphicDefault extends BitmapData {}
 
 // TODO: add updateSizeFromFrame bool which will tell sprite whether to update it's size to frame's size (when frame setter is called) or not (useful for sprites with adjusted hitbox)
diff --git a/flixel/FlxState.hx b/flixel/FlxState.hx
index 1fffa3b0ee..fdfd3d21f2 100644
--- a/flixel/FlxState.hx
+++ b/flixel/FlxState.hx
@@ -7,6 +7,7 @@ import flixel.util.FlxColor;
  * This is the basic game "state" object - e.g. in a simple game you might have a menu state and a play state.
  * It is for all intents and purpose a fancy FlxGroup. And really, it's not even that fancy.
  */
+@:keepSub // workaround for HaxeFoundation/haxe#3749
 class FlxState extends FlxGroup
 {
 	/**
diff --git a/flixel/effects/particles/FlxParticle.hx b/flixel/effects/particles/FlxParticle.hx
index a37411e5c6..fdcb928a17 100644
--- a/flixel/effects/particles/FlxParticle.hx
+++ b/flixel/effects/particles/FlxParticle.hx
@@ -76,6 +76,7 @@ class FlxParticle extends FlxSprite implements IFlxParticle
 	 * Instantiate a new particle. Like FlxSprite, all meaningful creation
 	 * happens during loadGraphic() or makeGraphic() or whatever.
 	 */
+	@:keep
 	public function new()
 	{
 		super();
diff --git a/flixel/input/android/FlxAndroidKeyList.hx b/flixel/input/android/FlxAndroidKeyList.hx
index 48d09b498e..01cfe765c5 100644
--- a/flixel/input/android/FlxAndroidKeyList.hx
+++ b/flixel/input/android/FlxAndroidKeyList.hx
@@ -7,6 +7,7 @@ import flixel.input.FlxBaseKeyList;
  * A helper class for Android key input (back button and menu button).
  * Provides optimized key checking using direct array access.
  */
+@:keep
 class FlxAndroidKeyList extends FlxBaseKeyList
 {
 	public var BACK(get, never):Bool; inline function get_BACK() { return check(FlxAndroidKey.BACK); }
diff --git a/flixel/input/keyboard/FlxKeyList.hx b/flixel/input/keyboard/FlxKeyList.hx
index ea8653833f..1bf17c4594 100644
--- a/flixel/input/keyboard/FlxKeyList.hx
+++ b/flixel/input/keyboard/FlxKeyList.hx
@@ -6,6 +6,7 @@ import flixel.input.FlxBaseKeyList;
  * A helper class for keyboard input.
  * Provides optimized key checking using direct array access.
  */
+@:keep
 class FlxKeyList extends FlxBaseKeyList
 {
 	public var A             (get, never):Bool; inline function get_A()              { return check(FlxKey.A);              }
diff --git a/flixel/math/FlxPoint.hx b/flixel/math/FlxPoint.hx
index bdf8830de1..ff7db38215 100644
--- a/flixel/math/FlxPoint.hx
+++ b/flixel/math/FlxPoint.hx
@@ -53,6 +53,7 @@ class FlxPoint implements IFlxPooled
 	private var _weak:Bool = false;
 	private var _inPool:Bool = false;
 	
+	@:keep
 	public function new(X:Float = 0, Y:Float = 0) 
 	{
 		set(X, Y);
diff --git a/flixel/math/FlxRect.hx b/flixel/math/FlxRect.hx
index b0cb109ede..a9c4433fb0 100644
--- a/flixel/math/FlxRect.hx
+++ b/flixel/math/FlxRect.hx
@@ -67,6 +67,7 @@ class FlxRect implements IFlxPooled
 	private var _weak:Bool = false;
 	private var _inPool:Bool = false;
 	
+	@:keep
 	public function new(X:Float = 0, Y:Float = 0, Width:Float = 0, Height:Float = 0)
 	{
 		set(X, Y, Width, Height);
diff --git a/flixel/system/FlxAssets.hx b/flixel/system/FlxAssets.hx
index 414ca96e4f..14414f8ceb 100644
--- a/flixel/system/FlxAssets.hx
+++ b/flixel/system/FlxAssets.hx
@@ -17,21 +17,21 @@ import flixel.graphics.frames.FlxTileFrames;
 import openfl.Assets;
 import openfl.utils.ByteArray;
 
-@:font("assets/fonts/nokiafc22.ttf")
+@:keep @:font("assets/fonts/nokiafc22.ttf")
 private class FontDefault extends Font {}
 #if !FLX_NO_DEBUG
-@:font("assets/fonts/arial.ttf")
+@:keep @:font("assets/fonts/arial.ttf")
 private class FontDebugger extends Font {}
 #end
 
-@:bitmap("assets/images/logo/logo.png")
-class GraphicLogo extends BitmapData { }
+@:keep @:bitmap("assets/images/logo/logo.png")
+class GraphicLogo extends BitmapData {}
 
-@:bitmap("assets/images/ui/virtual-input.png")
-class GraphicVirtualInput extends BitmapData { }
+@:keep @:bitmap("assets/images/ui/virtual-input.png")
+class GraphicVirtualInput extends BitmapData {}
 
 @:file("assets/images/ui/virtual-input.txt")
-class VirtualInputData extends ByteArray {  }
+class VirtualInputData extends ByteArray {}
 #end
 
 class FlxAssets
@@ -189,8 +189,7 @@ class FlxAssets
 	 */
 	public static inline function getBitmapFromClass(source:Class<Dynamic>):BitmapData
 	{
-		var bitmap:BitmapData = Type.createInstance(source, [0, 0]);
-		return bitmap;
+		return Type.createInstance(source, [0, 0]);
 	}
 	
 	/**
diff --git a/flixel/system/FlxPreloader.hx b/flixel/system/FlxPreloader.hx
index aba86f9902..347f2ee1ac 100644
--- a/flixel/system/FlxPreloader.hx
+++ b/flixel/system/FlxPreloader.hx
@@ -50,7 +50,6 @@ class FlxPreloader extends FlxBasePreloader
 		// super(0, ["test.com", FlxPreloaderBase.LOCAL]); // example of site-locking
 		
 		// super(10); // example of long delay (10 seconds)
-		
 	}
 	
 	/**
diff --git a/flixel/system/ui/FlxFocusLostScreen.hx b/flixel/system/ui/FlxFocusLostScreen.hx
index fe7c7f9e25..091cd8305e 100644
--- a/flixel/system/ui/FlxFocusLostScreen.hx
+++ b/flixel/system/ui/FlxFocusLostScreen.hx
@@ -9,6 +9,7 @@ import flixel.system.FlxAssets;
 
 class FlxFocusLostScreen extends Sprite
 {
+	@:keep
 	public function new()
 	{
 		super();	
diff --git a/flixel/system/ui/FlxSoundTray.hx b/flixel/system/ui/FlxSoundTray.hx
index da4d181ed8..b6d20b23ab 100644
--- a/flixel/system/ui/FlxSoundTray.hx
+++ b/flixel/system/ui/FlxSoundTray.hx
@@ -44,6 +44,7 @@ class FlxSoundTray extends Sprite
 	/**
 	 * Sets up the "sound tray", the little volume meter that pops down sometimes.
 	 */
+	@:keep
 	public function new()
 	{
 		super();
diff --git a/flixel/tile/FlxTilemap.hx b/flixel/tile/FlxTilemap.hx
index 95d591228d..df049122f4 100644
--- a/flixel/tile/FlxTilemap.hx
+++ b/flixel/tile/FlxTilemap.hx
@@ -30,11 +30,11 @@ import openfl.display.BlendMode;
 import openfl.display.Tilesheet;
 import openfl.geom.ColorTransform;
 
-@:bitmap("assets/images/tile/autotiles.png")
+@:keep @:bitmap("assets/images/tile/autotiles.png")
 class GraphicAuto extends BitmapData {}
 
-@:bitmap("assets/images/tile/autotiles_alt.png")
-class GraphicAutoAlt extends BitmapData { }
+@:keep @:bitmap("assets/images/tile/autotiles_alt.png")
+class GraphicAutoAlt extends BitmapData {}
 
 // TODO: try to solve "tile tearing problem" (1px gap between tile at certain conditions) on native targets
 
diff --git a/flixel/ui/FlxButton.hx b/flixel/ui/FlxButton.hx
index 6c87b079b6..606171166a 100644
--- a/flixel/ui/FlxButton.hx
+++ b/flixel/ui/FlxButton.hx
@@ -20,7 +20,7 @@ import flixel.system.FlxSound;
 import flixel.text.FlxText;
 import flixel.util.FlxDestroyUtil;
 
-@:bitmap("assets/images/ui/button.png")
+@:keep @:bitmap("assets/images/ui/button.png")
 class GraphicButton extends BitmapData {}
 
 /**