I was also looking a clip of Portal 2 not a FPS but is is a First person kind of game and twisted 3d puzzle...

Portal 1 sits in my top 5 single player games of all time, the combination of writing, game play and comedy come together beautifully. Some people complain that it's short but I think it's just right for the type of game that it is, any longer and it would have become too repetitive.

Ohh the top 5 single player games of all time aye?  Good call - mine would have to be...

5.  Dead Space

4.  Uncharted: Drake's Fortune

3.  Call of Duty 4: Modern Warfare

2.  WipEout HD Fury

1.  Oddworld: Abe's Exodus