Marvel Ultimate Alliance as the name suggests is a game which features a plethora of heroes from the Marvel Universe. Most of the heroes from the game are members from the most famous factions in the Marvel Universe such as the Xmen (Wolverine, Colossus, Storm, Iceman, Ms Marvel), the Avengers (Black Panther, Iron Man, Captain America, Spiderwoman, Thor) and the Fantastic four (Mister Fantastic, Invisible Woman, Human Torch, the Thing). It also featured loosely affiliated superheroes such as Blade, Daredevil, Deadpool, Dr. Strange, Elektra, Ghost Rider, Luke Cage, Nick Fury, Silver Surfer and spiderman.
The game is your standard beat em up kind of game the likes of Final Fight and Double Dragon. The game is however, a bit more complex as you also have to adjust each character's costume as well as his abilities. You would have to experiment which set of powers is suitable for you. In this aspect, the game is very RPG-like (roleplaying game).
If you want to get a feel of the game, you could start first playing simulations against such opponents as "The Russian Iron-Man"Crimson Dynamo, Kurse and Ulik. Then when you are accustomed to the gameplay, then you could go on the story mode and challenge Dr. Doom.
The game is fun to play with especially cooperatively. In my battles I have found that the game is best played with a tank character (a character that can take heavy damage and deals heavy damage) such as Thing and Luke Cage and a projectile basked character such as Invisible woman, Thor and Silver Surfer. Another thing that adds to the game is the possibility of finishing it with twenty six different chracters and experimenting with their different sets of powers. This provides plenty of replay value.
The downside to the game is a damage reduction bug which lessens the damage done by such projectile wielders such as Human Torch when playing with two players. There is also an overpowered time slowing power for such characters such as silver Surfer, Daredevil, Spiderman and Ms Marvel. While it does help you get through battles easily, it takes the challenge out of the game.
Overall, the game is pretty solid and is worth buying given the depth of the character roster and each character's abilities. There are also plenty of simulation stages which add to the game. The game is also very easy to learn but finding the right combination of powers and character would require hours of experimentation.