Really, loved this submission. I have only a few gripes, everything else is a compliment.
- The readability was straight bad. If the character has some sort of outline (like a white glow or something) or if they had a palette that stood out more, then it likely would have been better.
- The jumping felt awkwardly low. I would have preferred some "buffer" height to make it more comfortable.
- It was not clear when I took damage. I would have liked an obvious effect to accompany getting hurt. On that note, the attack sound wasn't super obvious, I didn't always know if I hit the enemy or not.
- The bug boss' teleport sometimes left it far away from me which was awkward.
- The fire boss' fire sprite was a bit hard to react to and the teleport wasn't annoying, but it did feel weirdly like a breather for me more so than the boss.
Alright, now for the compliments.
Despite the readability issues, the artwork is gorgeous. The environment art in particular with the backgrounds and tilesets look very nice. I always really like the diversity of environments.
I didn't really notice the music at first because of its volume. I realized there was actually music during the fire boss and decided to do another run through the bosses to hear the rest. Very cool sounding, especially the fire boss' track.
The powerup mechanic works well. Its simple but allows for all sorts of interesting things. Aside from hearing the music, the powerups is also why I was willing to do another run through the bosses; it gives a lot of replayability.
The boss's moves were really cool. Especially, the first boss. After dying one time to the first boss, I found his moves a lot more entertaining as I could then predict them. For instance, his smash-the-side-then-the-platform-move, became very fun to optimally time for maximum damage.
Overall, a fantastic submission. Proper fun gameplay.