This looks lovely! Great style and animation. Did you create the music too?
Light criticism: I'd like to see a quick transition animation between running and standing and (I dunno how reasonable you'll find this, but) I think you should steer away from collecting hearts and coins and think of a different way to propel the player. Something more... dream-like?
Anyway, keep up the good work!
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- Need help! I want some bats falling of the ceiling a lá Super Mario World. These bats need to detect the player ofcourse. How do I go about this without making seperate detectors? Comparing X's and Y's?
Yes, that's right. A simple box check should work. (A box based on the bat's position that extends downward vs. the player's collision box.)