Saw this on Twitter yesterday and followed you. I had lots of fun playing this last night. The bosses are TOUGH. I wish they had just slightly less HP. They have so much that the fight just feels drawn out. I also can't get used to pressing down twice to go through platforms. Can you change it to down and jump?
The controls are very responsive. I don't feel any lag whatsoever. Bullets are nice and bright so I can actually split my attention to other areas of the screen. All in all, this is really fun. You have a good project on your hands!