Very unique and overall a great entry. Nice clear graphics and a catchy track. My main complaints are small QoL issues. Losing your arrow input if the character isn’t stopped was frustrating at times, even if you were still holding it down when you pushed “move”. I would appreciate the move animation to be faster too, because there’s a lot of downtime moving around. Also worth mentioning that on my first playthrough, I didn’t realize you could fire again to reload. I ran out of ammo and fled until I died.
As far as gameplay/design, I really liked it overall. I found the regular bullet to be the best by far, with the artillery shot having uses. The other two I found entirely useless, and ended up jettisoning them when possible. It’s maybe too easy to cycle your shots, and the corridors made it easy to abuse the slimes. The 2nd level could also use a reason to not just run straight for the end.
Minor criticism aside, I think this is a very successful entry, so great job!