Another game in the Resident Evil franchise, but this time, it plays like an arcade light gun game. If you've played anything like House of the Dead, or Time Crisis, this game should feel somewhat familiar. The only thing you control in the game is your gun; the game is "on-rails", which means that the computer does the walking and looking for you. You do have limited control over where your character looks though, but it's nothing major and you can play and beat the game fine without using it.
It is not a very long game, you'll most likely get through the main story line in around 10 hours. But there are a whole bunch of unlockables, such as weapons, extra levels, and bonus content. If you want to get top scores in every level, and unlock everything in the game, prepare to spend over 20 hours.
For fans of the Resident Evil franchise, this game is a must play. It basically covers what happened to Umbrella Corporation and Albert Wesker, the main villain in most of the Resident Evil games. You'll revisit past Resident Evil locations, such as the Mansion in Resident Evil 1, the Ecliptic Express from Resident Evil 0, and Raccoon City from Resident Evil 3, plus some brand new settings exclusive to this game.
This is not a game to be played by children. It is moderately scary, and quite violent. You can decapitate zombies by shooting them in the head, blow them up by using a grenade launcher, or even break their necks. There are a wide range of enemies, ranging from zombies to giant spiders.
Overall, if you are looking for a mature action game on the Wii, then I'd recommend this game. It is possible to fully enjoy this game even if you are not familiar with the Resident Evil franchise, as it's basically the first 4 games mashed into one package.