Have you spent any considerable amount of time cursing at the monitor whilst trying to complete that addicting flash version of Valve's highly acclaimed first person action/puzzle game, Portal? If you have, or if you haven't because you were repulsed by a 2D version of Portal, you can now experience all of those levels in 3D. In Portal. The real Portal.
This is old news, yes, but I have discovered this map pack just yesterday. I was sceptic at first, because I had tried out custom-made Portal maps before, those that have been done by a Bethesda employee. The puzzle was complex enough to occupy you for hours, so that was good, but the level lacked in the design department. The Portal: Flash Version map pack includes levels that are clean, tidy, orderly.... they're simply spick-and-span. Admittedly, it's not Valve, but pretty darn close.
What pleasantly surprised me the most was that it actually deviates from The Flash Version. Those guys realise that if they stuck to the Flash Version to a T, it would ruin the map pack - what works in a 2D game doesn't work in a 3D game, after all. On top of that, they add in their own stuff, such as behind-the-scenes areas (you could think you play as the one who leaves all those signs that Chell discovers in the original Portal), and includes such references to the canon storyline as Borealis.
Overall, I was very pleased with this map pack, and it gives you almost as much playtime as the original Portal did, if not more. I highly recommend this map pack to all those that haven't tried it - it's fun, beautiful and extremely challenging.