I liked this dungeon-crawler type of puzzle game! Being able to power up your weapon fire fire or ice, and having different corresponding enemies and environments, was a really neat idea, and I think it worked well! Each enemy having a different weakness and movement style was also a nice touch, and it added some variety to the game. One thing I will say though is that the mechanic of different fire and ice powers felt kind of underused; I ended up going around just using default ammo, since I could only use the others very close to the powerups, and I didn't notice much difference in damage when using any other bullets. If you're looking to add some more action, then having each ammo type work further away, and maybe adding some special effects for each - splash damage or slowing down for example - might help improve that part of the game.
I really liked the art here! The use of the colour palette was great, and it made the game a bit more charming. The way each area has a different style, and each enemy looked unique, both made the game more visually distinct too. The animations added some feedback when playing as well. One thing I'd suggest, though, is some more visual clutter and variance - different tiles here and there, maybe some decorative pots or chests, stuff like that. It still looks very nice without it though, so don't worry!
The music was a good fit for the game, and I especially enjoyed the different sound effects for each ammo type, once again helping with the theme of hot-neutral-cold. A little bit of variance in them could've helped when repeatedly firing, though.
Overall, this was an enjoyable game, and there are a lot of things to do with it in future - a puzzle game, or dungeon crawler? Something else entirely? So many opportunities! Well done on getting this done!