All right, the new version of the OpenGL patch fixes the positioning of 4:3 videos, but does not fix the Leviathan crash.
I tried installing the new version of WCP Unlimited onto my GOG copy of WCP (installed via
Heroic), but the game just asked me to insert CD 3. Aside from that, the MUP seems to come with WCP Unlimited.
Here's a ZIP with a saved game on T'lan Meth 4a; Hopefully, that can help you find the issue.
BTW, if you're interested, you can find the
VOD of my recent livestream here. It will get automatically deleted from Twitch in 1 week, but
now it's on YouTube.