Ultimate Alliance 2 does not re-invent the wheel but rather smoothes out a few hitches from the original game.
Positive - The graphics looks a little better. It's so close to the original that it's hard to tell. The characters look the same but I guess the background looks more refined. Simplified is the special moves from the first. You have four major special moves to choose from, one for each button on the remote. Fusion powers, where you get to combine two superhero powers to beat bad guys, is a great added feature, however, it would have been nice to increase that option to 3 supers instead of a max of two. Two is still fun though. Even though there are only 24 supers to choose from in the game there's a lot more you can play against since this is off the Civil War storyline where heroes fight heroes. Another good thing is that you don't have to go back to HQ to switch out heroes, like the first game. If one of your characters is running low on health and you have no health boost to help him out, just switch him with etiher Wolverine, Deadpool, or Iron Fist. When your health is back up just switch your player back and away you go.
Positive + (Spoiler) - Stan Lee makes an appearance ... had me cracking up.
Negative - There are times the view is obstructed by walls when you move from one room to the next. This is the same problem that existed in the first version that wasn't corrected. During co-op play the framerate hiccuped and burped several times when the action was intense. This didn't happen frequently but enough for it to be noticeable. In normal mode there really was no challenge, it was rather easy. If you played the first game I suggest the Superhero mode instead of normal for your first play through. Camera panning was confused at times and when you play co-op you tend to wrestle with the other player in which direction the camera is panning - another porblem not corrected.
Overall - This is a fun game to play. Minor changes were performed to smooth out the game play from the first version but not significant enough be noticeable. Me and my son will have countless hours of co-op fun playing this game. I gave it a 7.5, a C+ in my books, because of lack of improvement, low number of playable characters, and ocassional camera frustration. It's still a great game to play and have if you love playing Marvel characters and liked the original. If this is your first time I suggest renting to see whether you like it or not.