Here's a dam map for ya. Yeah, the kind that holds back water. DM-Wrightsville can hold 16 blood-thirsty fragsters without any problem. The author, Steve Keene, suggests 7 to 9-players, but this seems too low if you really want some action.
The architecture is cave-like, with a large-ish, outdoor water reservoir for some long-range blasting. The outdoor area can cause a small lag, but the author made adjustments to keep this to a minimum. Tunnels are carved into the bedrock, and a few rooms with crates and electronic equipment also provide a place to trade ammo.
The textures were appropriate to the theme: Lots of concrete, rusted metal, pipes and block helped to make the experience more believable, not to mention all the rock.
The bots did their thing on most of the map: They swam like crazy, hopped around when it was appropriate, and remained on the lifts until time to depart. But I never saw them head to the waterfall for the damage amp even though the path nodes were there to guide them. And bad path nodes for the health keg and shieldbelt kept the bots from venturing for these little goodies. This makes for a one-sided match.
The lighting was a little dark, but this is a nighttime map, so I guess that's to be expected. The author placed some ambient sounds around for us to listen to, plus mover sounds and music, so this was appreciated. End of review.
For the author: There are some places where your path nodes are too close together, some places with no nodes (like the beam with the shieldbelt) and some places where the nodes are too far apart. You had broken nodes where you jump in and swim down to get the Keg-O-Health. Also, if you take that star texture in your skybox and select it and open the properties box, you can make the texture Unlit. This will make the black sky look very dark and the stars bright like they are really shining.