Great!
Being a fan of the classic side-scroller, this game brought back many fond memories. Thank you. Although it's a nifty idea to make the game consist of mostly bosses, this kinda gets boring and kills the replay value, I assume that you plan to make level type things where the levels lead up to the boss. Meh, that probably makes no sense, but then again sense doesn't exist at this ungodly hour. Well i guess you've played a side scroller so you get my point.