Fun game, I love the clean aesthetic. Level generation works well, though it did occasionally produce levels easier than the ones that came before them (one time I had a dungeon 11 that only had one enemy). The different weapon choices were cool, though I think having them just unlock rather than having to purchase them would make more sense since the points don't go down after a purchase. As a side note, I also use GameMaker and I would recommend incrementing image_index immediately when you first start moving, as otherwise the character will not animate when you move small distances, which can look odd.