JudasIscariot: Are you using Mint's drivers via its update manager or are you using the xorg-edgers repository to get your drivers?
I didn't notice the menu bits being missing on my system with nvidia-355.11. I think this might be a case where the drivers may need to be updated.
zpierce009: I've upgraded my video driver to the nvidiea-352-63. That's the latest release version nvidia.com shows for Linux. The problem persists. On other scenarios, it's been random and restarting a mission would usually fix it, but I'm on the second Warren scenario now and it's consistently not showing the bottom left portion of the UI, regardless of how many times I restart it. I can't switch weapons, can't view my luck levels. It's a pretty tough mission and I haven't been able to beat it due to the handicap.
352 might not be enough as I played the game on Mint 17.2 but I also had a specific repository added that allows me get a driver version higher than nvidia-352.63. I know that the game works as intended on nvidia-355 and up as I've played it on 355.11 :)