If I'm not wrong, the clouds are not sprites, they are procedurally generated. They look awesome!
I really liked the aesthetic, and I loved the dessign of the monsters. And also the detail you took for adding the death animation! And the melody of the song, its very catchy.
Very complete game. The only thing I missed it was some kind of score or monsters killed.
As a suggestion, if you still working on the game, it would be cool if the butterfly could interact in some way with the monsters.
PS: I liked a lot the text after game over screen haha.
Congratulations for the game!