I just bought the linux version via Humble Bundle. Installed grimrock under ~/bin/grimrock/ and started it ... which results in the main menu screen showing up, and "flickering" every second, and the mouse cursor resets to the center of the screen. Music plays, and I can interact with the main menu somewhat (eg. pressing enter goes to the options, as that's hilighted).
Debian testing, 64bit, nvidia driver, lspci says NVIDIA Corporation GT218 [GeForce 210] (rev a2)
EDIT: Solved by editing "~/.local/share/Almost Human/Legend of Grimrock/grimrock.cfg" and setting resolution to slightly lower and changing displayMode to 2 (windowed)