I'm reasonably sure my problem is a variation on the theme of the OpenGL bug I've seen reported here, but...
I'm playing the game through Steam on Ubuntu (16.04, upgraded to latest) using an Nvidia video card.
Like the Windows user in another thread (which has been marked 'done,') the game crashes randomly after so much playtime.
Unlike him, it's not just the game. I have to hard-reset my computer.
I've tried updating all drivers, etc. The issue persists.
There was a recentish login-loop issue involving Ubuntu and nvidia; I had to apply the fix for this.
Needless to say, this situation discourages me from playing.