Two stories to play, two times the fun.
First off, X played excellently in this game. It had everything. New weapons, armor, and enemies to obliterate. Bosses started off just right and later in the game, you're in for a challenge! The bosses were normal. Each had a different attribute which gives you different abilities.
When you beat the game you're done...if you thought that you are so wrong. Once you beat X's story, you get to play as Vile! At first, I thought it was a stupid rumor just to bring your hopes up, but no, you can play as him alright. The difference is, going around the second time is a lot harder! The enemies are tough from the start, and they only get tougher! The good thing is you get more weapons at your disposal.
To conclude my review, I'd like to say that any Mega Man fan with a PSP should check out this game. You'll have so much fun with it. I give it two thumbs up.