Great tracks and new online play make Mario Kart Wii one of the best games in the Mario Kart series.
The first issue I would like to touch on is the Wii Wheel. This is a plastic shell in which players can insert the Wii Remote and then use to steer their karts like real cars. It felt a bit strange at first, but it quickly became the most preferable form of control. Hardcore players should take note that there are many other ways to play the game, but the Wheel holds its own and actually works very well. This brings me to another addition: bikes. The bikes in MKWii turn a little more sharply than karts and cannot powerslide as well. Whereas karts get two levels of powerslide, bikes get only one. On the flipside, bikes can do wheelies that will give players a slight boost on straightaways. The two vehicle types come off as pretty well balanced. Both can also perform tricks when going off of jumps by shaking the Wii Wheel around. Tricks provide players with a boost when the vehicle hits the ground.
The other major addition made to the MK formula for MKWii is online play. Although many probably wince when they hear the words "Wii" and "online play" in the same sentence (I know I often used to), it really seems as though Nintendo is starting to get a handle on this whole online gaming thing. Whereas the last Nintendo game to feature online play, Super Smash Bros. Brawl, was limited to four players and plauged by lag, Mario Kart Wii supports a whopping 12 players and has never lagged on me once. Think about that. Even hugely popular online games on the premium Xbox Live service lag at times, but Mario Kart Wii has never shown signs of slowing down. Online play works similarly to that of MKDS, where players will vote on which stage they wish to play on and the computer will randomly choose one out of that list. In addition to the traditional VS mode, Battle modes are now available for online play. There is the classic battle mode, which has recieved an update (presumably for the more casual crowd) and a new mode in which players must collect coins. In this mode, the team with the most coins by the end of a match wins. The streamlined battle mode (players can no longer "die;" when they lose all of their balloons, more appear) feels pretty good because you'll never be stuck spectating after losing all of your balloons. There is also a MKWii channel that you can download to view high scores and ghosts for your favorite levels, but I don't really use it. All in all, the online play is a big step in the right direction for Nintendo.
Aside from the addition of the wheel, the core racing component of MK will be familiar to fans of the series. Powersliding has been altered a bit in order to discourage snaking, which contributes greatly to making VS mode fun again. It must be said, however, that the single player difficutly is very spastic. Players racing in 50cc mode will probably never lose a race. The 100cc races are definately more difficult, which might come as a surprise to some players. Part of this difficulty comes from the fact that this mode only allows bikes, and the sharper turning and sliding will take a bit of getting used to. But once you get to 150cc, it becomes clear that there is nothing you can do to help yourself win. Just start the race up and hope that you end up in front of the pack. Seriously, the catchup AI in 150cc is heinous. Items strike without mercy and in rapid succesion; enemy karts seem to teleport in order to catch up to you. In short, you will have very little say in whether or not you win a race in 150cc mode.
In spite of its difficulty and its general similarity to other Mario Kart games, MKWii remains one of the best games on the Wii. It may not have as much new content as Brawl, but it's often just as fun.
Graphics: 8/10: Solid - for a Wii game. It's no Mario Galaxy, though.
Sound: 8/10: I think you all know what to expect in this department.
Gameplay: 9/10: The Wheel works well, and races are a ton of fun even if it does all come down to luck in 150cc.
Entertainment: 9.5/10: Aside from the frustrating higher difficulty level, this is one of the most entertaining games I've played recently. Online play and new battle modes make this worth a look for even those who've denounced Mario Kart.
Overall: 9/10