Portal Tunneling
I was going to ask you about this! After you changed the height of those three platforms in the most recent version, that was the only way I could figure out to set up the fling. I felt a little guilty, because I really dislike portal tunneling and I want to be able to declare that it's always cheating. This puzzle is the only convincing counter-argument that I have yet encountered. Kudos!
I discovered tunneling as a solution to the turret-room in Advanced Chamber 18, which I really had problems solving.
Anyway, I like tunneling, and it's not that hard to avoid, just place a few nonportal walls, and if that doesn't work, you can at least make it a real pain in the ass for tunnelers. IMO it's a more advanced way of solving chamber 15, hence Valve kept it for the challenge.
I have long thought about making a map were tunneling was meant to solve a puzzle, but since it's not an "official" method, I'll just make it an alternative way of solving a puzzle or completing a map. But I do support making a tunneling map, as long as it somehow at least indicates that tunneling is required (or just inform the player).
The whole "not official" thing is what really bugs me. All they would of had to do is teach tunneling in the game (just like they did with everything else) and it would have opened up a lot more options.
Even if I make a tunneling puzzle and label the map as very had, some people will still call it out as an exploit. That being said, my map currently has 2 advanced tunneling rooms.
If people really hate hate those rooms, I might pull one out - but the 2nd puzzle is pretty ingenious/hard (or at least I think it is 
) and I would love to keep it in.
As long as your puzzles also include other tings than tunneling and people are forewarned that tunneling is required, I think most people will accept it.
They probably found tunneling in the beta-testing or something and concluded it was a more "advanced" way of solving the puzzles, like skipping chamber 16 (or whichever) where you can skip the whole chamber by flinging up the final elevator.
But the point is Valve has included tunneling in one of their own maps, and therefore can not be counted as cheating or an invalid way of solving a puzzle, placing a few nonportals should stop most tunnels
(and the momentum-gathering in the Logic Portal maps is also not included in Portal, but I haven't heard anyone calling that cheating...)
I didn't need tunneling in any official portal maps. If you did, you're doing it wrong.
About logic portals, that is valid because you learn momentum gathering in Portal.
About logic portals, that is valid because you learn momentum gathering in Portal.
It is required for gold in chamber 15, portal challenge!
Placing two portals at floors at different height and gaining momentum (only restricted by the height of the ceiling) by flinging from the higher into the lower one is never taught in any of the regular chambers.
It's not important whether a technique was taught in SP Portal. That's not really a strong argument either for or against tunneling. I don't think that line of discussion is likely to get us anywhere.
Let's look at a few "non-standard" (non-taught) techniques on which Portal players are near-unanimous:
A. Propping open doors with crates, turrets, and cameras. This is never required or taught in the SP game, but I think you'd be hard-pressed to find many players who would call it a cheat/exploit. A lot of impressive Challenge runs use this technique.
B. Non-standard flinging. This includes the floor-to-floor momentum-building technique, as well as flinging puzzles sensitive to angle/trajectory (Play Shmitzchamber for lots of examples). Again, these moves weren't taught by Valve, but there's no contention in the community about them. In fact, we love unusual flings.
C. Wall-climbing. This is when you repeatedly drop/pickup an object while jumping and facing a wall. If you time it right, a glitch in the physics system will "bump" you vertically up the wall in little increments. You can do this indefinitely unless your fingers give out. There's no controversy here. Every right-thinking person considers this an illegitimate exploit.
I think this is very illuminating. It seems to me that we accept A and B as legit for two reasons:
1. They're consistent with the established behavior of the game world. They follow certain rules and produce (mostly) predictable results.
2. They take some genuine thought and skill. Using these tricks in a challenge run often takes more creativity and skill than the intended solution. They're not just a braindead way to skip to the end.
Wall-climbing fails both these tests. It's totally inconsistent with the normal physics simulation, and it really takes no finesse to use it.
I think that portal tunneling also fails both tests miserably and should therefore be considered an exploit. Or more concisely: If it looks like a cheat, feels like a cheat, and is used like a cheat -- It is a cheat.
I find tunneling to be legitimate for the following reasons:
It is required to achieve Least Portals Gold on map 15.
The developer commentary includes a mention that they considered killing a player who was standing in a portal that closed, yet decided against this.
Nerbacular Drop allowed not only tunneling but firing a portal projectile through another portal, which has a superset of tunneling's implications for puzzle design.
Nothing wrong with portal tunneling, IMO; its a natural extension of what the game itself illustrated (and used in the challenge maps). It makes no sense to me to have people complain that the Portal game itself was too easy, and then limit yourself to ONLY the techniques they showed you in training. 
Solving a puzzle is often about creativity and "thinking outside the box"; this is one of those cases, and the fact that almost anyone can do it just illustrates how basic a move it is. It just doesnt "feel wrong" to me.
And as other have said, its SOOOO easy to stop if you want to do so on a map. If you want to stop it, just take away the vertical portal walls in that part of the puzzle; make them use the floor or ceiling only. That will take out 95% of people right there (there are still specific ways to still do it, but you would require either a very special setup or some darn fancy portal jumping (I was able to do one of those in Accident Prone as an alternative to the official way to solve puzzle#2). Another way to stop it that I did in a map of my own; I LET them make those portals on the vertical tunnel wall in the distance. . .and suddenly they are faced with 1-2 turrets sitting on that opposite wall they couldnt see before, locking in on their position. . .they have to quickly concede that portal tunneling simply isnt going to help them there. The map-maker has CONTROL over this if he chooses to.
Some of the more obvious physics glitches (wall walking, etc). . . now thats another story. I dont like puzzles that REQUIRE physics glitches as a part of the solution; thats just my preference. And there are a number of glitches out there; I designed up a situation where I could actually use one end of a portal to repeatedly fire the other portal to any portable locations, on any orientation (up, down, etc). . .and I dont even have to be IN the portal at the time! Scary stuff. . .
Correct me if I'm wrong, but isn't wall walking just advanced-tunneling?