It's good to see that you're utilizing differential shading properly, although in one or two places it's still not that convincing. In terms of flow, there's no glaring problems, and there's good variation in floor/ceiling heights. We're around a classic Marathon: Infinity level map at this point.

There's something flickering that looks like a teleporter but isn't. Please fix. Also, some platforms aren't as obvious as they could be, and a few raised portions of the map (with ammo) are irritatingly just out of reach. Bad in a net game.