I can see my house!

Or... I can see myself watching myself watching myself watching myself ...

Portal is a great game. The ending is superb, one of the best I've seen. The bonus levels are hard, the challenges are even harder and sometimes ridiculously so. The limited step count ones can be crazily difficult as they are very dizzy-inducing. Using a minimal number of portals is also challenging, but much more doable, as is the time-attack version.

So, the really quick review: Portal is a game based around a simple utility weapon: It can create portals. You shoot a projectile than when it hits a wall/ceiling/floor, marks it with a particular color (orange or blue) ellipse. When both colors are marked, a portal is opened between the two ellipses. Total momentum when traveling through the portal is preserved, but the direction changes to be relative to the ellipse. Energy is not conserved. This sets up some really crazy puzzles and uses for the portals, and within the context of a puzzle game it also sneakily develops a creepy plot. It's not a very long game, but the ending would be worth many times the effort it takes to get there. Now I just have to wait for more levels, by either the devs or perhaps the mod community. :)