Before we start with the Portal 2 walkthrough let's do some short history (yes, really short).
Back in the year 2007 when Portal was released on steam everyone interested in interesting games talked about it. And the cake (that was a lie) was also heavily discussed. But this was well deserved, the game was the first 3D puzzler ever (better and anyways than Myst) and featured a cool story with a lot of humor and great gameplay, so it was just plain fun to play Portal.
So the expectations for the second part were even higher, but Portal 2 is longer, has a lot more varied settings, and is as funny, if not even funnier than the first part. The different gels are a welcome addition to the portal universe. The only critic I have is that the levels are very linear and there is only one solution most of the time. The first part was different with that and a lot of different solutions for a problem were possible. But Portal 2 is a really funny and interesting game and just rocks.

And that's why you can read my solution for Portal 2 here and it begins just below...
Enjoy!