Plays like standard Uno with red, green, blue, and yellow cards (25 each color) numbered 0-9, with skip, draw, reverse, wild and wild draw four cards. In addition, there are four additional "War Machine" cards for a total of 112 cards for this version. War Machine cards count 50 points in scoring and make you impervious to the effects of draw 2 and draw 4 cards by making your opponent draw those cards.
The Iron Man 2 version of Uno is listed in the main Uno Wikipedia page under "Theme packs". The Iron Man character is prominent on the bulk of the cards, with other characters from the movie used on the skip, draw, reverse, etc... cards.