Keystone is essentially a remake of Foundation from Halo 2 with a few minor differences. Some of the proportions/placement may be slightly off, but this was the best I could manage going from reference pictures. I attempted to maintain the bleak appearance of the original by using light textures with a bright orangey glow enveloping the map.
[Update 1] Fixed lighting so that there is now contrast and shadows.
[Update 2] Replaced geometry crates with map models.
[Update 3] Added ambient sound effects.
[Update 4] Modified lighting, sounds, and textures, modified weapon placement, added team colors and team spawns/flags, changed particle effects, removed several map entities, fixed clipping, and modified the map geometry.
[Release 1] Added trim to the spawn room walls, some retexturing, lighting, and additional detailing.
[Release 1.1] Deleted the crate models in the main arena area and replaced two with geometry crates.
[Release 1.3] Drenched the map in team colors with a bit of unrelated retexturing.
[Release 1.5] Now only two team colors. (The four team version can still be found here: http://www.mediafire.com/?tonwg3yzxyz)
I don't know why any training facility would have a public restroom out in the middle of the testing grounds, but it has one nonetheless.
This map is currently configured for a six person deathmatch or a twelve player CTF/STF game.
Feedback is always appreciated.
[**Update**] Sept. 12, 2010
New RE compatible skybox and new texture.
Sorry about the screenshot, I am running the game through Wine and screenshot keybinds do not seem to work.