Nice Work!
Well, overall, the engine is fairly solid, being based off a Mega Man game and all. It definitely has the feel of a Mega Man game as well, difficulty and all. Like with the classic games, I couldn't get past the first boss (LOL)! Haha, if I kept at it, half the day would go by and I might have figured out a way to beat the boss, heh. Perhaps make the bosses a tad easier, though. I've noticed the difficulty of the bosses go from semi-tough to beat, to easy about halfway through (when Mega Mman has about 50% of what he has to get - power-ups, etc., and then from there it gets harder and tougher to beat from there. It would provide a classic learning curve for a game like this. Overall, this game surpassed expectations for a flash-based Mega Man game. Just perhaps decrease the difficulty and make it a tad easier to dodge the bosses attacks (as a pretty bad Mega Man gamer, I can say in most boss fights I've managed to get about 50% of the major attacks dodged on the later games on a bad run, while here I was hardly able to dodge. perhaps add a sound or some form of him as to where the first boss comes from, like a distinct sound from each direction, or something.)
Great work, keep it up!