Gateway 2 is a robotical point and click by Anders Gustafsson. In this game you need some basic knowledge about physics and time. Codes and secret places... Remember that sometimes things need time, and therefore this game is (in it's own way) very realistic.
This game continues from the previous one, Gateway. You are now grey and you need to look for video tapes to help a girl. Watching the tapes helps you to understand what has happened...
Good luck!