Looks nice indeed -- being on a school pc at the moment, I can't do any playing, naturally. If you're getting slow framerates, which seems a little unlikely even for a big "room map" as you describe, I'd suggest this:

• Did you use func_details? I believe those are the best brush entities to use for microscopic brushwork, particularly stuff that can't be seen from any notable distance.
• Scale up your lightmap grid? You know that strange "3D LightMapped View" in hammer? If you have not, I suggest turning that view on, and scaling UP the light map grid on any brushes that do not recieve much direct light. Such as, detail brushes, faces on brushes that are hardly ever seen, etc.
  
  Remember: Bigger light map grid = less polies yet uglier lighting. Naturally, the converse of that results in more polies and prettier lighting (at least I think that's how it works.)
  
• Did you use the nodraw texture on faces that would never be seen?
• And of course some models. Those brush-based lamp posts look a bit... well, ugly I s'pose. Those were the only real eyesores I saw in all of the screens, and chances are, a low poly model would have looked much better, and done better justice for your framerates.

So yea. Hopefully I'll get a chance to play it today, since it looks damn good. I think the gameplay will come off just fine -- the ingenuity of players must never be underestimated!