One of the most unique games I've ever played.
You have two systems of hints in the game. The first is that objects that are important to your progression that are nearby are colored red (most of the environment is colored in a white or very light blue steril looking color...so the red really stands out). The second is that you can hold ALT in order to have your character automatically look in the direction of your objective. Otherwise, everything is left up to you to figure out. It does very little hand holding and progresses at a rate that makes sure you don't feel overwhelmed.
The game as a whole is mostly an adventure/platformer in first-person view. You will have times where you can knock out people and take their guns, but all you have is the one clip that was in the gun, then you have to discard it. Also, holding anything but a pistol will greatly hinder your ability to run, jump, climb...etc. Because of the way the game plays, it feels like a huge adrenaline rush almost the whole way through, with minor head scratching moments of puzzles that mix up the pace. One thing I find intriguing is that people (including the GameSpot review) seem to say there is an overabundance of frustrating trial and error, but I honestly found all of the puzzles and platforming to be logical and intuitive all the way through.
The controls for the game, as a matter of fact, were extremely effective and intuitive for me. I never felt frustrated when I was trying to navigate the environment (except when I would fall to my death beacuse I jumped too early...which is clearly my error).
The puzzles are easy to solve because of how cleverly everything is placed and how they look. In fact, the game looks absolutely beautiful. Even though the environments are relatively simple, they look absolutely brilliant, vibrant and very pleasing to the eyes. The audio is also very very immersive, from the footsteps, gunshots, voice acting and heavy breathing when you run a lot...the game is an aboslute aural pleasure. To top it off, the music was appropriately calm or upbeat depending on the situation, and definitely fit the mood of the situation.
The main problems with this game are that it is extremely short (took me 5 hours on Normal) and I didn't see any worthwhile reason to collect the collectibles in the game. I will admit that though the game is short, the time trials definitely gave me plenty reason to come back and keep playing...especially since you upload your times and compete with friends. It was a nice little touch that definitely helped make the game more of a value overall.
In the end, at the price the game runs out now, this game is one of the most unique first-person experiences you will ever have. I will be bold and say it is just as fresh and unique as Portal was when it released. If I had to categorize this game I would say it is a First-person aciton/adventure/platform/shooter. It is a very enjoyable experience that everybody should try.
Graphics: 9/10
Sound: 9/10
Gameplay: 8/10
Replay/Lasting Value: 6/10
OVERALL: 8/10