Just tried to boot it up after the install and I'm getting godawful flickering; it gets even worse once the first mission is started to the point of being so bad I can't usefully get back out of it except with a hard reboot (alt tabbing still leaves the flicker).

Played another version on this computer a while back and don't remember this problem. Some kind of graphic setting nonsense?

No problem with my game about this.

I don't experience any graphical issue with the game. There was a lot of trouble with the different versions that backers of the game try in the past, but for what I experienced til now all was corrected, so maybe something in you computer are causing the trouble?
Try with the usual suspects (verify integrity of the game files, make a clean installation of the drivers...).

I don't know right now what options the game offers to tweak "in game". You can also looks for the .ini file and try to modify the refresh rate, the tipe of double or triple buffering, vertical synchronization on or off, among others related.

Checked the usual things (updated the drives, turned off V-sync and fiddled with some of the other toggles) and made no difference. I'm trying a reinstall just on the off chance it matters.

I'm sorry to hear that, not cool. I can't think of what might be causing the problem.
Maybe something related with power supply? Or if you play on a laptop the battery or something.
Hope reinstalling it fixes it. Good luck.

And it turned out the reinstall worked like a charm, which I didn't really expect. A bad bit tweaked somewhere or a slightly dodgy sector on the drive, I guess.

Computers can really be black magic sometimes...

I'm glad to hear that. It is always the first proposed solution "reinstall the game" and it does not usually work, so we, not without reasons, don't expect that in the end it will. Computers...

Yeah, I only bothered because nothing else had worked.