It's funny that as often as ghosts appear in games as enemies, there are very few where you actually control a ghost.The possibilities for what could be done are quite creative, and the developers behind Geist new this. Geist is a Gamecube exclusive that is quite innovative, and which, like Metroid Prime, is primarily a first person exploration based shooter. It's also one of only two Nintendo licenses to be rated M, the other of which, Eternal Darkness, is also on the Gamecube.
Geist centers around a man named John Raimi. Raimi is a scientist, but also a member of a counter-terrorism team. this team was sent in to inspect the Volks corporation only to find that they were creating biological weapons. While attempted to escape the facility, Raimi is captured and he is used in an experiment in which his soul detaches itself from his body. Throughout the game, Raimi, in his ghostly form, is attempting to get his body back as well as shut down Volks for good. It's a very entertaining plot, and a bit mroe adult than what Nintendo would normally do, but there are some plotholes, although they are quite small.
As you play the remainder of the game as a ghost, there are many advantages. to spirits, the rest of the world moves in slow motion, and on top of this you can possess many object and creatures. This is used quite inventively in some boss fights. For example, in one fight, you must possess an enemy soldier, at which point the boss will throw a grenade at him. Leaving your host, the grenade is now in slow motion, giving you time to possess it, and cause it to explode on the boss instead. being a ghost also has disadvantages, however. If an object s not possessed for more than several minutes, you will cease to exist.
In order to possess a living being, however, you must first frighten it. For example, you could possess a trash can and cause it to rattle, drawing them over, and then use the object to frighten them, and then possess their body. When in combat, potential hosts are already in a frightened state. It's a really cool mechanic that makes you think from time to time, as certain hosts will have clearances others will not, and certain animals can reach things others cannot as well. This system also brings to light, however a fatal flaw. The fact that you can possess things should mean that some of the puzzles should be much simpler than they are. For example, there is a portion where you must possess a solider and then use a computer to generate a password, which you must remember and input into an electronic door lock...well, why can't you just possess the electronic lock and manual force it to unlock, or even break it? They should have made such things possible, as this would reward quick thinkers.
The controls aren't bad, but they feel kind of clunky from time to time. I guess in a way that reflects what it might be like to control someone else's body, but at the same time, you'll sometimes wish for slightly better precision when engaging enemies. That's not to say the aiming is bad, because it's actually quite fluid, but some of the controls feel awkwardly placed. I did eventually get used to them, but they never felt natural. Luckily, the c-stick never gave me any problems with aiming, which I expected it to do because of its size.
Geist has high production values, and looks and sounds great. Some enemy voice overs are laughable, but most of the main characters are done quite well. Graphically this game is on par with others in the genre at the time, such as Halo, though in my opinion is actually has better animations than that game, especially the faces. It's not among the Gamecube's best looking games, but it certainly helps prove than the system is good for more than just bright, pastel Mario games.
Geist is somewhat short, but it does have some collectibles for completionists to go after. It's quite innovative, and feels very unique among other shooters, but unfortunately the controls never feel quite right. Still, it's very cheap these days and it's something I feel should be experienced by all Gamecube of Wii owners. It also has a multiplayer mode which is quite fun in you can find 3 people to play with. Nothing quite gives the virtual middle finger like possessing your friend and forcing him to kill himself in the dumbest way possible. If you ever stumble across a copy of Geist, it is well worth your time, and its uniqueness has helped it stand the test of time well.