TrAVel
An enormous 6-level total conversion. (Well, okay, not total... and that's its biggest weakness.) The mapmaking is pretty good, and the new creatures are quite cool, but I was bugged a bit when a new monster, with lots of new looks/sounds, died with an old sound, or fired with an old sound, or... Okay, it's a trivial complaint. Overall, this is really, really well done. It's been out for a while (as have lots of the recent uploads), but it's the first time I've seen it, and maybe you, too. Lots of art, lots of sound, lots of music (that's where all the new size comes from).
Levels in map "Map":
TrAVel Inc. Headquarters
Downtown
Metro
Government Building
Asteron
Sanctuary