Wow, great to hear you were able to finish your first game, especially in such a short time! When it comes to screen shake, it isn't used to make the game any harder but it helps the game feel more immersive or as some people call it "Juicy" or feel here's a few videos I found that helped me understand what Game Juice was
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Obviosly color wouldn't apply to this game,But maybe it can help in your further game dev endevoursObviously