The art being unpolished was my fault. This was my first time making a lot of art for a game so I didn't even consider how pixel sizes would affect anything. The level design for level 3 was meant to feel haphazard to show a sort of run down place, but the other levels definitely needed polish. For the falling level the point was that you jump into the fire and basically never hit the ground so you stayed safe, though I didn't make that very clear.
Overall, the game was mostly unpolished because of a lack of time. We were going to have an artist make the art but he was busy part way through so art took time away from coding and design. Thanks for the helpful feedback and it's definitely given me things to look out for in future games!