I got this game for Christmas. I was really looking forward to it coming out in the UK as I am a huge Pokemon fan, but had never played on any of the Colosseum games, only the GB/GBA games.
When I played this game, it was definitely not a disappointment. I played this game non stop, unlike other reviews I think the graphic's are really good for the Wii. Another really good point to make about the game is the DS/DS Lite connectivity. This allows you to upload all your pokemon from Diamond and Pearl into the game and battle with them in the game, and buy (with the money earned from battling in the Closseums)and download items that can be used in Diamond and Pearl. Further more, you can battle with other players by using your DS/DS Lite which is very fun indeed! I also liked the fact that you could choose what your trainer looked like in the game, and buy items to customise their appearence using the money earned from battle. The online play is also really fun!
However there are some criticisms of this game. In my opinion it did not have much of a story line apart from the constant battling. The next criticism of the game is that it does not take that long to complete, and once you complete the game the only thing you can really do is do it again on different levels of difficulty unlocking new things from each Colosseum- personally I find that quite tedious.
Overall this game is a must have for any Pokemon fan. It is fun to play, and in my opinion has good graphics. Be warned, that to get the most out of the game you need Pokemon Diamond and Pearl on the DS/DS Lite.