Since this game is merely a short button-masher, the only reason you should play it is if it came with your Xbox.
The gameplay is simple button mashing. There are different fighting combos to use, but there are hardly any and some are far too powerful in comparison to others. So, most of the time you'll be pressing the same button combinations to attack. There are also some sequences in which you must tap and press contextual buttons, but they are in no way unique to any of the other fifty thousand games that have button-timing mini-games. There are several boss battles in the game, but none of them are particularly interesting. The graphics in the game are shiny, and alright during gameplay. But in the cutscenes they appear much better, especially in the facial animations of the characters. The comedy in the cutscenes is great and matches the feel of the film. The characters from the movie all have the same voice actors that voiced the film characters, and they all do a great job. It's also great to hear Jack Black voicing Po and saying little narrative monologues in between each level. So, I don't really recommend renting this. Just look for a friend who got their Xbox near Christmastime and borrow it from them, because they got it for free. That way you'll be sure to get your money's worth.