Great entry! The graphics are awesome, and the music is outstading!!
I would consider adding a checkpoint system. if you get blasted by one moster in the end of the stage you have to make all the way through the stage again.
Also, some instructions on the controls may be interesting. There are no explainations about the move and the jump, I tried WASD for some time before realizing I had to use the arrow keys and the up arrow to jump.
I like how you took the time to add more and more powerups! It makes us feel like we're really progressing!
The second part of the game when we can't shoot enemies anymore is really hard! we have to wait for the immaterial stone to recharge everythime there's even a tiny bit of lava in there, so we won't die and return aaall the way back when dying. in that part, the lams are in really tiny platforms, so we have no way of jumping in safely without being immaterial. that made the game really rough, since the lams have such a huge knockback and if we get hit by them we will almost surely go into lava.
I would also consider adding variable jump height to make shooting enemies easier (on the first part of the game) and to have more control over platform jumping.
Oh, and on the first stages, you can shoot the enemies all the way to the other side of the stage. I guess making the projectiles being destroyed when hitting a wall is very important in that case.
I absolutely love the animation and the song when getting a powerup!!
I played it all the way through, and for a jam, it was an amazing entry! It was all rounded all the way, and I'm really impressed you made it in only 3 days.
Also, the particles and animations are simply amazing!!!
Nicely done!!!