This is a quick bullet-hell game with a fair bit of potential. I like the character-switching concept and the art looks great. Enemies and bullets are clear, but maneuvering around the map feels a bit limited since I can see enemies on the edge of the screen but I can't get to them until they've had some time to live and shot at me some. This can be compounded if a few enemies are missed as the bullet patterns eventually converge into an un-dodgable mess. A few things that would be nice to improve would be to have the background scroll in the opposite direction of the characters (right now it looks like they're just running in place) and some additional sound effects for shots, damage, and explosions.
It's a good start. I hope you keep at it!