Rednog said:
Just to comment on the time played, I talked to my roommate this morning and he said he finished it in about 4 and a half hours his first play through, 2nd play through in about 2 and a half. And I've been hearing from various other people on my steam friends list that they've done it in 4-5.
I personally have yet to get a crack at the game because my copy is somewhere in the mail...
Unless they're cheating or exploiting the game systems in some way, there is no possible way you, or anyone, can beat Portal 2 in 2 and a half hours. Even if you know exactly what to do all the time, it will still take
at least 5 hours.
If they're going by what the Steam timer says, they should know that the Steam timer is broken. I once played New Vegas from day(about 5PM) to night(was 10 when I got off), and Steam says I played it for 2 hours.
Steam Timer is broken, it is not a good way to tell how long you've played a game. Best way to do that is to not the time when you start, and note it when you stop. Then just use simple maths to figure out the difference.
But Portal 2 is not 4 hours long. There is no possible way, except with cheats/exploits, to beat the game in under 5 hours.