A nice, simple, and fun game! I like the music and visuals a lot. Although the gameplay was fun and the delay on the butterfly made things a bit difficult, because of the few bullet pattern and just one bullet type i was able to find some "sweet spot" on some of the level where you couldn't get hit at all. An interesting approach tackle to this problem would be "forcing" the player to move around. Maybe adding some types of rhythm elements like Osu! would be interesting. Overall a fantastic execution on a simple game, would love to see some more variation in gameplay!