hey, I've been looking forward to this =), first of all, amazing work here, congrats on making this map, it's the most beautiful map in urt imo.
just some notices from me
You have the welcome text at the start of the map, in all languages. I myself am dutch and I think :
Instead of writing : "meer informatie over de telepoorten wordt versterkt bij de receptie", you should write : "meer informatie over de telepoorten kan verkregen worden bij de receptie". This is the way to say it in dutch, normally.
Also over textures are brilliant and the map is almost perfect. I especially like the shiny textures in the ventilation shafts. however I found some things that you can improve.
1: this texture looks really bad in comparence to the other ones :
2: this ventilation looks a bit too bright imo , perhaps you can make it more dark, grey
so thanks for making this map and I look forward for any other projects you may have.