Great visuals with interesting and unique gameplay make this a rather good game.
As the gameplay begins, you'll notice it has very simple and generic first person shooter gameplay. You won't be amazed by any new and innovative features, everything in the gameplay has been done before. You'll move from location A to location B. You'll end up getting a good different variety of weapons to use. One interesting feature is called your "Spirit Walk". Once going into Spirit Walk, you leave your body and use your spirit to move around whether it be through shields to help navigate the levels. If you are blocked by a shield barrier, go into your spirit walk and turn off that barrier.
Spirit Walk is a great feature, but it also is a downright terrible one as well. Once you die, you go into a mini-game involving your spirit. You'll have to use your cherokee spirit bow to shoot strange creatures, and the more you shoot, the more health you get. It makes the game extremely easy and can get rather annoying at times as well. The enemies in the game speak english, which is a little strange. The AI goes from good, to fair in certain gun fights. Some of the best gameplay is when you use what is called a "gravity walkway", in which you'll be able to walk on ceilings and on walls... and in certain occations you'll be confused which way in "up".
The graphics and sound are good, nothing spectacular but good nevertheless. The music is very well composed, but it's the voice acting and the sheer great ambience in the levels which takes the cake. The game uses a modified version of the Doom 3 engine, which means it has some great visuals no doubt about it. The game has some impressive character models, and impressive environments. The frame rate is quite steady, and from the weapon effects to the screams and even some amazing radio comments with Art Bell make the sound in this game great.
In closing, this is a goog game which will give you 14+ hours of good gameplay, an interesting plot, and some features which might actually creep you out a little bit, and make you have some great times, especially with some of the wacky mutiplayer level designs.