The game crashed for me once but I beat it the second time though.

It's a bit buggy and I was able to skip almost every puzzle just by jumping over the obstacles.  Jumping in general seems too powerful and needs to be nerfed, I think.

You have a lot of unique art assets here, you clearly put in a lot of effort.  It looks nice.

I really do like the idea of changing the world by changing elements.  It reminds me of some classic games like Chrono Trigger - changing the past - or A Link to the Past - moving between the light and dark world.

The puzzles are all "pick 1 of 4 elements, and 1 of them will work."  This means that even without the jump-cheat, you can brute-force all the puzzles in a few seconds.  I feel like all it needs to clinch the puzzle mechanic into something challenging is some interaction between the 4 worlds.  A puzzle where a change in one elemental plane affects another.

A minor nitpick is there are a lot of interruptions to the flow of gameplay.  Each tutorial/hint sign rips control away from the player and each element change requires switching screens.  I hope you can streamline this more in the finished game.

You got an impressive amount done in the span of this challenge and I hope to see you develop this idea further.  Good job!