The following opinions should not dissuade you from giving the game a try and are simply the words of a grumpy old datahead expressing himself. Feel free to give the game a try if you're interested.
I remember giving this a try some time ago and strongly disliking it. The music was too loud and of extremely poor quality, the controls were not very good, most of the enemies didn't work like they were supposed to, the camera was horrible, and there were various other problems with the game I can't remember. I think it had to install something on your computer and/or browser to run, as well.
Naw... if I want 3D Rockman action, I'll go play 8-Bit Deathmatch for a while. It's repetitive, like all multiplayer-only games, but at least it's relatively bug-free and stays faithful to the source material.