"CHEATED" was a fail
ok in the timed, portal, steps maps it says CHEATED all the timewhen i complete it.. i have no idea what to do in lvl 13... i did it right. like you should.
the right way to comlpete it ... wtf?
they should have made you able to complete lvls even with noclip... its peoples own choice if they want to complete it without cheats 
(not saying im going to use cheats if it was that way...) i think its stupid ..
instead of posting stupid comments cant you just tell me how the actual way is to complete it without "CHEATS"?
How to cheat the Advanced Chambers and get your achievements.
1. Load Advanced Chamber Level
2. Open Console Type in Sv_Cheats 1, then type in Noclip
3. Fly to the very end and undo noclip
4. Type in Sv_Cheats 0, Hit Escape, Save Game
5. Exit Game
6. Restart game
7. On Main Menu Screen Open Console and Type in Sv_Cheats 0 just to make sure it isnt still on
8. Load your save
9. Walk into the elevator
10.???????????
11. PROFIT!!!!!!!!!!!!!
i do it still says CHEATED i even completed the level the RIGHT way.. its so baad programmed
funny how the fact that you can't beat it means its badly programmed.. i have beat every challenge (and the advanced challenges) by more than the "gold" standard. never seen that. (aside from when i actually did cheat, just goofing off)
you are either A) setting sv_cheats to 1 so that you can cheat, or B) sv_cheats is defaulted on for some reason (which it shouldn't be unless maybe your config file is set to read only (which is possible))
as far as a LEGIT way to CHEAT thats an oximoron.
as far as how to beat level 13 goto youtube. type in "test chamber 13" and whatever challenge you want to beat (ex: test chamber 13 least steps (or least portals) (or least time))
and they DO allow you to beat the chambers by cheating, if thats what you want to do, but they do not allow you to get the achiements for it. (aside from finding some exploit *stares at portal?FAN?*)
That's my guess.
figured out it was that.. :S i just compiled a map so it has sv_cheats on so that the programmers can noclip around the map to make testing quicker