If we want to talk about something different, than we have to talk about portal. This game is awesome.
You are a test subject in a facility. You get a portal gun and you have to solve puzzles. When I started to play, I was a bit disappointed, because I thought I will just have to solve the puzzles and that is it. When I got further, however, the game became more and more interesting.
Puzzles became harder, and things started to become scarier. When I arrived to the end, I was so excited, I did not want the game to end.
The puzzles themselves are not that hard, they are fun to do. When arriving to the end, however, things change and start to be interesting.
My rating for this game is 10 out of 10.