It's a neat concept and cool art style, but I'm not a huge fan of the gameplay currently. I didn't really care much for the randomly spawning projectiles as obstacles, especially since the randomness leads to inconsistent difficulty. I would have preferred regular enemies or obstacles.
The mechanic of changing shapes is cool (even if I've seen it in a lot of other games in this jam at this point) but feels pointless outside of the scenario they're introduced in. Of course this could easily be remedied if the game had more levels.
I do like how you implemented coins throughout the level to find, it reminds me of Nintendo platformers like New Super Mario Bros. Maybe one thing you could do with the coins is have it show how many of the total coins the player collected at the end of the level?