While we all know the NVIDIA Linux driver works fine with this game, after finding out that it's possible to get the Mesa/Gallium3D drivers working, my next focus was on seeing whether the Catalyst binary blob would work for this game. Surprisingly, it appears to!
The game fired up fine on Ubuntu 15.10 with the packaged fglrx/Catalyst driver. In the few minutes of initiating a new game, I didn't notice any apparent rendering issues.
So at least the game appears to be playable, but I can't confirm the entire game works fine on Catalyst. Unfortunately with XCOM 2 lacking a benchmark mode, that's to the extent of this round of testing and about as far as I'll get with this game.
Eric Griffith will be sharing his thoughts on XCOM 2 gameplay under Linux in the days ahead.