Pixel art = A+ . Very nice style my man. The main mechanic is pretty solid, although a bit tedious/hard to keep track of both the player body and the player projectile. Especially since they share controls. But it was still a pretty fun.
When battling the boss(es) , upon death you respawn just a moment before entering their area. Since there is no place to get coins and no area from this point forward that have any coins, the boss fight becomes really really difficult.
The rest of the critique I can bring forth are based of off this being a very wip project, so I think won't bore you with them. This is neat, keep it up!