On my course (I study Computer Games Design) Theres a few guys working on a multiplayer portal Mod, I havn't seen it in action yet but one guy told me today that they could get either 16 or 32 players going all with 2 portals each. Madness. I dont think they got a website or anything but if they do i'll post it here.
I looked this up (multiplayer portal) about a week ago. Currently, Valve hasn't released any SDK for Portal, which makes it difficult to make any mods for Portal or based on Portal. If you look on Youtube, there are some videos of people trying to do it anyway. But I couldn't find anything showing people using portals with other people. Just people running around with the Portal player model and being able to pick up barrels and other crap. Nothing major.
I tried the exite mod for HL2 (it came out way before Portal) I'm pretty sure it has multiplayer, but it's so buggy. The system that the portals use to clone objects is much inferior to Valve's.
It's gonna be hard but would be awesome if we saw an online mod. I think one of the problems is that when you're going through a portal and you go through the other one on the roof how is it going to animate you flipping around? If you know what I mean.
