Great game! I love using the gun to jet pack around.
The art feels very crisp, it’s easy to see what’s going on with the background being the right shades of the same color so it’s not clashing with the foreground, a small detail I appreciate. I also like the parallax effect that background objects have, along with the character, particle effects, and enemy animations. It makes the game feel polished and I can tell you spent a lot of time on it. Also I appreciate that you have a save system in place, which is impressive for a game jam game!
I agree with some of the other posts on the controls and bosses. Some feel too punishing, the attacks need to be a bit more telegraphed to give more time to dodge.
Also I think you run into the same issue that I did when making my metroidvania submission, which is to say that they are really hard to balance. I spent too long on your spider boss not knowing that you can get health upgrades later, which makes the fight much easier.
Overall, I can tell you spent a lot of work in the game. Good job!