Ghost Squad is the first, true rail-shooter released for the Wii. Released by Sega and is a pretty faithful port of the original arcade shooter, containing all the quirky humor, bad plot, and campy voice-acting that made the original so great. Not to mention, for being under 30 dollars, a must-have for any Wii collection. The game has three modes: Arcade, Training, and Party. It also has great control customization and online score monitoring.
The training is mode is pretty much straightforward, and one which I spent as little time as possible on. The Arcade is what I've been playing the most of, with some Party off and on. Arcade contains three missions, each scaling in difficulty and new paths as you progress. As you successfully complete levels and paths you are rewarded with new weapons and costumes - including my favorite: the panda suit! Some of these rewards really add to the replayability, by making some paths easier or more difficult. It also allows for a second player to jump in at anytime with one button press - something I wish more games put in.
Now, you can play this with the wiimote seperate or with the nunchuck. You can also the Wii zapper, but truth be told, I'd rather go with a third-party gun like the Nyko Perfect Shot. In any case, this is where customizing the controls become a must - you'll find you'll want to change that action button from A to something else.
Ghost Squad is a must-have, especially if you're a fan of arcade shooters. Perfect for parties and by yourself.