For Riskers, the GTA-like Top-Down-Shooter which was just released yesterday for Linux, is now the Update #2 on Steam available, which fixes a lot of Linux-specific bugs:

Reduced police spawn rate
Increased sports cars top speed and acceleration
Some cars are now more damage resistant
Minor tweaks and fixes
Fixed the no sound issue (Linux)
Fixed 2 mouse cursors showing up (Linux)
Fixed cutscenes (Linux)