http://pc.ign.com/articles/610/610994p1.html
On the second page, Willits reveals some absolutely fantastic news (to me, it's fantastic, anyway).
He said it's "mathematically the same" and to me, the implies that the physics will be extremely, extremely similar. That is way cool.IGN: How much can you say about multiplayer?
Tim Willits: That's another great question. The multiplayer is based on the Quake III physical feel. You know, it's mathematically the same. As a developer, you don't want to totally change the way everything feels between multiplayer and single-player, but we felt that we really needed to do that in Quake 4, so when you play multiplayer it's totally different than single-player. You'll have teleportation pad, jump pads, your bigger combat maps you're familiar with from Quake III. Deathmatch, plus there are CTF variants.