Not bad; but needs much improvement.
Graphics: Subpixelised, people don't "hold" items. They float there. Backgrounds are absolute crap. You get a 5 solely for the nice looking interface.
Style: Good I supose.
Sound: Not bad.
Violence: More like lack thereof.
Interactivity: It was fun! Well, at least until it started being really gay with the glitches. And also, not enough friction. Far too little friction in fact. And the hits? WTF? And Mega Man X(notice the X; there's a difference between the two) has no Melee moves. WTF. All buster shots which actually don't help you as much as you think. And the recoil. FFS. The recoil gives me nightmares. Seriously, X plays a lot like Samus. He has a buster. He can fire off faster shots for a good amount of damage, but he can charge it for a stronger shot. He can fight. He's shown to do Hadokens and Shoyrukens in two or three games.
Humour: None.
In other words: it's bugged. Massively bugged. Fix it and show me something I can play. And seriously. Up should be jump. And give us two or three keys to attack with. Normal, Special, and Grab/Dodge/Shield. Also, attacks do far too much damage. I get hit like 3 times and I'm at 130% thrown off the map.
Regarding Link, you can stack his down attack infinitely if the enemy doesn't move. You should make him move to the side a bit so he doesn't rack up 400% in like 10 seconds.
The break the targets stage sucks. Too large and similar in each room. The run to the finish is horrible. Monsters knock back far too much. You didn't add the hit -> extra jump feature that was in all the Smash Bros thus far which made it harder when you were swarmed.
Complaints aside, good game. Had fun for a while.