This was actually such a fun game. My first run I found that I ran out of ammo and it ended pretty fast but on my next runs that wasn't an issue. The sounds an ambience were great and the speed in which you got upgrades felt really good since it didn't take long.
One thing I'd suggest is to make it clear when the player is out of ammo or make it reload automatically after shooting whilst you have an empty mag. Of course, the art could do some polishing - the player, tileset and rocket and effects like the rocket flames and death burst effect all felt like they were from different game rather than a cohesive single game.
I think if it took inspiration from vampire survivors where you keep your upgrades after a run could make this game really hard to put down!
All in all, this is a solid entry, that beneath the simplistic art has some solid gameplay and is fundamentally fun. A great proven concept!
Also the thumbnail art looks great - Am i right in thinking it's AI generated? Midjourney maybe?
Anyway, great effort, keep it up!