So, it happens as well on Desktop versions, therefore, unless that issue is fixed with the latest version (which in this case I need help to implement), do you have any idea how to mitigate this afterimage that happens after closing the game?
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I'm a bit confused about what you mean by afterimage; are you saying something remains on the screen after you close the game? This asset isn't doing anything nonstandard (it all comes down to drawing a fullscreen surface in a Draw GUI event), so if you find your game isn't closing correctly, this might be more of a bug on YoyoGames' side or perhaps a driver issue. If you can provide a bit more information to sittingduckgamesco@gmail.com, I can at least ascertain whether or not I can resolve your issue with a patch to the asset pack.