If you follow anything related to the game Portal, you may know about the flash version of the game that brings the game play mechanics of portals and their effects on physics to the realm of 2d.   The 2d flash version was on the receiving end of a lot of hype, and made players think of Portal in a whole different light.

Now, a bonus map pack   for Portal has been released that brings all 40 (plus some more) levels from the Flash version into the real Portal 3d environment.   The new maps introduce some slick game play elements like electric fields, and a lot of time-pressured puzzles where the player must figure out what to do before being crushed.

The level designs are really quite well done, better than most Portal fan maps which just try to throw you in a maze of incredibly difficult tasks and expects you to just make portals in the exact right spots that the map maker wanted for you to win.   There are a lot of tense moments in the levels, and I can tell that I haven't played a first person shooter in awhile because I felt the sensation of falling physically in my stomach as I made an infinite loop of portals and fell for 30 seconds.

If you didn't have enough Portal with the single player campaign, then check this out.   They claim it will add a whole 3.5 hours of playtime to your Portal library.