For direct access use https://forums.oldunreal.com
It's been quite a while since oldunreal had an overhaul, but we are moving to another server which require some updates and changes. The biggest change is the migration of our old reliable YaBB forum to phpBB. This system expects you to login with your username and old password known from YaBB.
If you experience any problems there is also the usual "password forgotten" function. Don't forget to clear your browser cache!
If you have any further concerns feel free to contact me: Smirftsch@oldunreal.com
I made a version back in like 2011-2012 with zombies and various bunkers, and I did one for another map that was similar to zeitkind. i wonder if i still have it, i thought it was pretty sick due to the pathing of the zombie hordes.