Huh, not too shabby! It's basically a cute Undertale-esque SHMUP boss rush, and it does a decent job at providing a good variety of boss patterns, as well as some goofy twists and turns like the guy who runs out of bullets, haha! I also like that it has some strategy to it, such as where you can optimize your damage by switching to the gun that only fires upwards, but faster, when it is appropriate.
In terms of feedback, the game is a bit rough. In general there's a lot of minor jankiness with animations and transitions that are a bit awkward. Additionally, I played for a long time without realizing you had another weapon and a grenade because it doesn't teach or provide a HUD that you could intuit this from. Speaking of weapons and abilities, it's also a bit strange that it doesn't provide any cooldown timers on the HUD, making me unsure whether I could throw the grenade or dash again yet. I also wish the damage/health was equalized across the board instead of being surprised when a boss attack does so much damage for some reason. I also just got really confused when the game changed characters to this blast jump dude and the jump controls were weird and glitchy and I had no idea what the game wanted me to do.
Despite its roughness, this was pretty fun at its core and shows a lot of promise in creating varied combat scenarios!