Simple execution, very stylistic, and carried out well...and awesome to boot! Great job, man!
Now, what you OUGHT to do is try to make a complete Megaman game, with Megaman going into several different NES games, each with their own boss and special weapon to gain (like Samus' weapon would be "You got Ice Beam" or something). Other suggested sidescrollers would be one of the Mario games, Castlevania, Kirby, Contra, Kid Icarus, Ninja Gaiden, etc.
If you want my suggestion as to what to do for future installments of the game, try this: make it so that one of the final bosses of the game is a re-programmed Megaman that you have to fight! ^_^
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