Решение:

make a backup of the ScreenSelector.so file in the Plugins folder:

cp ~/.steam/steamapps/common/Rust/rust_Data/Plugins/x86_64/ScreenSelector.so ~/.steam/steamapps/common/Rust/rust_Data/Plugins/x86_64/ScreenSelector.so.bak

copy the ScreenSelector.so file from the Legacy Branch to ...Plugins/x86_64

cp ~/.steam/steamapps/common/Rust/Legacy/rust_Data/Plugins/x86/ScreenSelector.so ~/.steam/steamapps/common/Rust/rust_Data/Plugins/x86_64/ScreenSelector.so

Launch Rust! the screen settings dialog is skipped and after a tense moment of darkness, the cilent will begin to load.

Start banging on trees and barrels with your rock!

http://support.facepunchstudios.com/feedback/view/2872-rust-not-starting-on-linux-after-last-update