1. There is a .BAK file inside the zipfile. This explains why it is so big. Since 99,999% of time nobody will be interested on backups, remove it.
1.1. BTW, the ogz file is already zipped, so there is little or no improvement by zipping an ogz file (unless you want to pack more than one file).
2. The map modelling looks nice. It is interesting to explore and jump around on that map. I'm not sure if that would be a good map for DM. Maybe it could be a good capture map (with a few modifications).
3. Lighting is bad. There are some places too dark.
4. I'm not sure if there should be more weapons around. I did not found many of them. I guess you should put one (or two?) weapon(s) inside each "house with a health inside".
5. Like Xsaii said, we need more ways to upper floors. Maybe jumppads or ramps (instead of just stairs). Most of time I was at ground. When I finally got to "middle level", I fell back to ground.
6. Add some "noclip" or some "sky texture" above each of those outer walls. This will avoid people falling outside the map area (say, after a rocket-jump).
7. Yes, my older hardware (Pentium III 800, GeForce FX5500) suffered... 15fps on average. Maybe you could change the lightprecision value to improve performance?
In overall, could be a nice abstract map, with some polishing.
