You put a lot of work into the graphics and it shows! I had a little bit of confusion about how the game worked, but eventually I picked up on it, and I don't see any major issues. Here's a few notes:
- I'm not sure if this is a bug or not, but sometimes I see a coin with a box, on rare occasions a coin with no box, and mostly just the boxes. At first I thought maybe it had something to do with vision vs sonar, where maybe it was an indicator of something found but not seen, but going back to observe a box closer without collecting it didn't change how it looked.
- The collider for the player just being the tail end is a little wonky. It's serviceable for picking up coins, but there's one upper-right corner of the map where I got stuck because I ran up to the edge, turned around, and my tail was stuck in the wall. I think it depends on how much acceleration you have while that happens, but it's something to note.
- I did take damage while trying to remove the sand, and I'm not sure what the cause of it was. The boss wasn't near there or anything.
Otherwise, great job!