From the first level on, Ultimate Alliance takes on a very dirty and nitty-gritty look. Environments are being destroyed (either by you or some external event) and the harsh lighting typically casts deep shadows onto the metal floors and glass walls. The locations aren't the only things that come off nicely. All of the characters (be it the generic grunt or one of the specific characters from the comics) appear as they do in the standard time line. I make that distinction because although "Ultimate" appears in the game's title, it doesn't take place in the Ultimate universe (which should be easily recognized by Nick Fury's um... more traditional ethnic background). Let's just say, if you have a system that can support this game's non-trivial minimum requirements, then you will definitely be pleased with what you see.
Soundwise, this game seems to have it done right. In-game conversations between your heroes and NPCs (when there is actual talking involved) sound as they should. Thor's Nordic accent comes out crisp, while Iron Man has a distinctive metallic sound to his voice, and Wolverine sounds just as gruff as he always has. And the game's music is very motivating and orchestral and thus really pulls you into the action of the game.