Nice puzzles, although I'm a bit torn on the ending (spoiler warning).
The graphic effects and artstyle used during it are pretty good, I kind of wish the entire game looked like that, but if it did then the ending wouldn't have the shock factor. Choices are hard.
Another nitpick that I have is the last monster's design. Why a dog, weren't moths the theme? It feels a bit too jarring, although the monster itself looks cool.