There are collision errors where the player is unable to walk through what should be open. I tried testing for circumstances or specific locations, but it seems to be mostly random.
I only noticed this once and it may have been coincidence, but it seems player movement lags for a second when the music loops.
Level 11 was significantly more difficult than the levels before it and the levels after it felt easy in comparison.
This occurs only once or twice, but it's frustrating when the player needs to jump over spikes but goes off the top of the screen while jumping. Maybe either extend the play area or add a shadow to indicate the player's horizontal location? Or is it just supposed to be difficult in these cases?