There seems to be a few people facing an issue of the game not loading up the initial KoTK UI and title screen, not allowing them to progress to the main menu selection.
We believe there is a workaround that should work for the time being.
1.Remove the UserOptions.ini file from the directory
2. Launch Z1BR from Steam
3. Issue should be resolved and likely in full screen. Enjoy
4. Go to the Options to select windowed mode if that is your preference.
-You can copy the .ini over to the desktop to not lose your settings and reference what you had prior.
This is a work around for those facing this issue, until we can better identify the cause and fix it at its source.