The 3rd stage of the annual John Van Caneghem Tournament (2010).

No one has ever completed the "On One Breath" map in offline mode.

That's incorrect ;)
I'm telling you again, there was a tournament called "Knights of Honor," and it had something similar. That is, you could save and interrupt your playthrough (you can't sit at a map for 2 days straight), but you could only use load saves 1 or 2 times. =))
;)