Greatest Mega Man game in the entire franchise, just so much fun start to finish. Took everything that was good about Zero 2 improved and expanded on it. The level design is just as great, and the combat (specifically the combo system combining EX skills and normal attacks) has been fully fleshed out, giving you a ton of freedom for how you approach enemies and (especially) bosses.

And I don't care what anyone says, the story was cool as fuck. I actually cared about what was happening throughout the series, and it culminated in the best finale in the Mega Man franchise.