Didn't expect to found this kind of Metroidvania style in a GameJam. You did and outstanding job with this game. Very well done!
The levels are amazingly well designed. Had fun completing them all. Last one was really tough... lost soo many times (one at the last jump, with the door already opened, fall into a set of spikes :( But tried again and ended it.
Also found a weird bug when jumping. I'm used to jump with W (old retro habits), but when grabbed the fire elemental, notice when jumping with W, the player shoot a fireball. At last level, when I need to shoot at the exact moment to kill the slimes, this was annoying, so start using the spacebar for jumping. Great... The issue came when my brain mix both jumps, and press W and spacebar in a moment of rush... and the player jumps like if I had a wind elemental Level 20! Doesn't happened always, but I manage to reproduce the issue several times (I didn't use as an exploit, swear it!)
If you're planing on expanding the game, would be nice to add more variety to the music. It's a great track, but feels repetitive after a short time playing.
Great job! Congratulations!