About a couple of months ago I purchased a physical copy of Portal 2 for the PC. After typing in the serial number it came up with a message saying that I need to play the PlayStation 3 version and link my Steam account to it. At first I thought the store gave me a wrong serial number, but after getting another one, the same message popped up.

The reason why I got the stand-alone PC version was because I could it for $7, so I was sure as hell not going to buy a PS3 copy as well. Luckily my local Video Ezy had a rental copy available, so I paid $7.95 for a 3 night rental and performed the Steam link there. Afterwards I was able to install the game on the PC and play along fine.

I don't have a high-end gaming PC, it certainly wasn't high-end 3 years ago either, but it played the game on almost full max specs, with minimal lag. I've yet to beat the game, but I'm definitely enjoying it so far.