Here's the thing. I 'Ignored' pack0.dzip warning, installation continued... it updated my .NET Framework so hahaahha good luck with that, didn't it break the game for many in 2.1? Anyway, I restarted the computer and the game launched just fine. Except the menu is mangled/invisible until items are highlighted and the game turns into a disco with missing objects that blink all colours of the rainbow. Obviously, because I skipped pack0.dzip update.
Congrats, every update of your PC games has been horribly broken. Why mess up the track record now, right? :/