A pretty neat demo of two walkways on top of each other. The technique uses scenery items to fake the look of the walkway, so you don't look like you're floating... it seems pretty clear that with a little bit of artistry, the proper scenery items could be created to make the upper walkway look nearly flawless. Also contains an intriguing extension of the author's untextured wall experiments.

From the master of cool tricks comes a bizarre, but thought-provoking idea... a mechanism by which you can determine the difficulty level at which someone is playing. The included demo simply has different terminal messages for each difficulty level (kindergarten through total carnage), but you could, in theory, use the technique to decide where to send a player, depending on what level he's playing on. The possibilities are pretty far-ranging...

A large football field, surrounded by seats (?). Nicely laid out, if a little bare... but ammo is really sparse, probably for anything more than two people. Gets a little better once you find the entrance to the control booth, but it's still not enough for bigger games.

A huge arena surrounded by rising hallways. With big groups, this might be fun, but smaller groups would have a hard time getting close enough to kill. There's a switch in the central pillar which I don't understand at all... all it seems to do is make the upper hallways vulnerable from below. Since only those in the upper hallways can flip the switch, it seems, well... pointless. (I suppose it also makes the area around the hill targetable from above... but there is much more freedom of movement down below, so it's more dangerous to those in the passageways.)