The supports are there to show that the roof is still under construction. (Hence why the ceiling is like that. Might not be so obvious because of dev textures, but I'll make sure to make it look better in the versions to come!
The roof is clipping through the skybox, its just a small visual bug which I'll be fixing
Thanks for the feedback!
Just so you know, .zip files can't be played on the server. I'd suggest repacking the .bsp or zipping it into a .bz2.
Overall, there's not might height variation, but it still looks great nonetheless. Good luck with the future of this map!
Looks like your download is broken due to the site getting messed up a few days ago. Click "Post Download Update" in the Overview tab; and reupload the same file and change the version string on the site with "<current version> Reupload".