Portal Tunneling
Be good a Portal. Duh. That's why it's Gold achievement.
Have you tried doing that challenge without tunneling? You can be as "good" as you want - gold isn't gonna happen without tunneling.
well, just a thought:
It took this guy 21 seconds to get up to the part where he needed tunneling: http://www.youtube.com/watch?v=pFgvWhfEGzo
Then 4 seconds after the tunneling part to get to the end...
leaving him with 29 seconds in which to do the part where he tunneled without tunneling.
- I guess the question now is if it's possible to land on those track pillars without falling so you can cross safely and keep it under 29 seconds.
Okay I'm ending the "can you do gold on 15 without tunnelling" debate now: http://www.youtube.com/watch?v=g89iKoJxgKc
It may not be the way Valve intended 15 gold to be done. It may even be that Valve intended us to use tunnelling. Who knows?
However arguing that tunnelling is an official part of Portal because of 15 gold is invalid.
Footnote: I like tunnelling.
Leave it to Player1 to always find the hackiest way to beat a map. 
Good work.
Good work.
I did it the same way... So yeah, take that people who think it's not an exploit. Last I checked, standing inside a wall was an exploit, which is essentially what you're doing while tunneling.
Don't use it as an excuse to say that tunnelling is an exploit. Just because it wasn't necessarily part of the original design doesn't make it an exploit.
The argument "standing inside a wall is an exploit" is completely moot here because the whole basis of the game is the fact that you create new openings in walls (dynamically created user placed doors if you will). Or is it an exploit to stand in a doorway between two rooms?
In my book speed-crouch-backward-jumping and phys-prop-wall-climbing are exploits whereas tunnelling is not. The dividing line between exploits and non-exploits is, as others have put it in this thread, that exploits abuse obvious bugs in the game engine which both of those above mentioned are, where tunelling is a direct byproduct of actual game mechanics. Exploits can be removed by fixing bugs. The non-exploits can only be removed by redesigning the game.
I wouldn't like maps to require exploits to complete, however all exploits are fair game when doing real ultimate speed runs of course.
(In a completely unrelated note: Somebody make a map with a grenade launcher or something where you have to do a grenade jump to get momentum for a fling... Please!!! 
)
Think about it, you're standing inside the wall all the time during portal, not just while tunneling.
Even if we can't agree on whether tunneling is an exploit, I think we can certainly all agree that whatever the heck Player1 did is an exploit.
Old thread is old.