I got to get a chance to play around in Rogue's Quake II mission pack, Ground Zero while in Dallas (Redwood, Zoid, and I probably outstayed our welcome, as we found ourselves at Rogue waiting for the Sin demo release, but the Rogues were nice about it). Here are my impressions based on a couple of hours with the game

I experienced a bit of single player, and enjoyed it (but I think proof of single player is whether it captures you enough to play through to the end, so the jury is out there). I didn't encounter any of the new enemies they're working on, but I got to experience some nicely enhanced AI on some familiar ones, like a Berzerker who merrily hopped after me as I tried to escape across the top of some machinery (they normally won't follow you past a crack in the sidewalk), and fliers who circle strafe you when the opportunity arises. The enhanced AI, and some dastardly level design made the single player action considerably tougher than Quake II or the first mission pack, and I actually was forced to save games between levels.

There are some new weapons in the pack: A proximity mine launcher and placeable tesla coils that zap anyone who gets too close can make for some nasty traps. The nailgun makes a (hopefully Internet friendly) return, called the ETF Rifle now, but a flechette by any other name.... Also returning is the down and dirtiness of the old fashioned chainsaw (removed from a dead Strogg lumberjack, no doubt), and the Plasma beam, which actually is more like the lightning gun from Quake than the Plasma Gun from Doom.

Deathmatch is clearly a priority, as 10 of the 24 levels in the pack are DM levels, and the game offers new power-ups specifically designed to add a little discretion to your carnage: killing an opponent who has a  Vengeance Sphere means facing, well, vengeance (it's funny to see a guy with a Quad damage run away from you). And then there's the Anti-matter Bomb (da nuke), which you have to be pretty savvy not to blow yourself up with, not to mention the dreaded Quad damage Anti-matter Bomb, sure to destroy everything on the level, including the one who dropped it (Dr. Strangelove would be so proud). In spite of the thrashing from the Rogue guys, who enjoyed our helplessness at their hands (especially Zor, who's a sadist), I had loads of fun deathmatching the pack (and at least I got to whip up on somebody, though I won't name any names so as not to embarrass Redwood).

It will be fun if Ground Zero catches on for multiplayer (it doesn't seem that the first mission pack inspired that many DM servers), because while maintaining the Quake II feel, as befitting a mission pack, the deathmatch has a different style from Quake II and the variants I've seen, and I always welcome the opportunity to chainsaw someone, or hell, nuke 'em in a pinch.