Still the best-selling title in the series (and rightfully so), Mega Man 2 took the formula of the first game and completely revamped it.

The graphics were improved, the number of bosses increased, the crushing difficulty eased a bit with the inclusion of energy tanks, and the game was given a password save system that would let you restart the game from where you left off.

Capcom cranked the sequels out pretty furiously after its success. (We know, Capcom making sequels? Crazy!) But they couldn't hope to compete with the glorious second installment. When they decided to go for a retro feel with Mega Man 9, it didn't think about Mega Man X and had to look back to this game.

Perfect level design and puzzles, a memorable soundtrack and unique bosses made for one of the best platformers of all time.