I'm in an underground cavern right after Wheatley goes mad. There's an upper and lower catwalk as well as a circling catwalk ascending into the ceiling. I tried everything, but I can't seem to fire a portal anywhere that will do me the least bit of good. I'm reluctant to receive the answer outright, but I will gladly accept a friendly hint. Also, I know I am 2 years late on this game. It's from my shame pile, sue me.

You have a screenshot or something?

Ah, I've decided to pack it in for the night...but it's in the area with the sign warning you not to lean on the railing, if that helps.

Sorry, cant recall the section from memory.

When I used to get stuck I would brute forced most puzzles by just locating the "portal-able" surfaces.

Ok, um...how about this then: https://www.google.com/search?q=condemed+testing+area+portal+2&ie=UTF-8&oe=UTF-8&hl=en&client=safari#hl=en&q=condemned+testing+area+portal+2&spell=1

That sounds similar to a place I was stuck on. It turned out that there was a white portalable square off in the distance somewhere that I hadn't seen.

@sometimesavowel: Image isn't working, without knowing specifically where you are a walkthrough is the best I can give you, sorry

http://www.youtube.com/watch?v=jsL7ph0u42o

Yeah, the underground part has a ton of what are essentially pixel hunts where you have to find the one surface in a cavernous area that is painted white (thus portalable). Usually it's somewhere nearby, but not always. I think the Cave Johnson dialogue is some of the funniest in the game, but I REALLY did not care for some of those big open areas that were either easy because you literally just make a portal to cross a giant space, or frustrating if you keep overlooking the one area you're meant to portal.

It's in the area immediately after that giant vault door that opens onto that comically tiny door.

Look into the half-opened door next to the staircase.

Got it, thanks!

I had never played the original Portal and still CRUISED through the lab portions, but almost EVERY puzzle from this moment onward caused me GREAT inner sadness.

I think I remember what you're talking about. I think I cheesed that section (IE I honestly can't remember what I did to get past that).