Several players have reported issues when connecting to multiplayer servers.
Game itself works intended frame rate but menus are locked to 30fps. There's no solution to this and developers are aware of it
If you see this error (when running Steam from a terminal):
/bin/sh: /home/labyrinth/.local/share/Steam/SteamApps/common/Sanctum2/Sanctum2: /bin/sh^M: bad interpreter: No such file or directory
the ^M indicates that the file is DOS-formatted, so the newline is confusing steam and/or Sanctum2. Various editors have ways of converting the newlines. Here's one way you can convert it using vim:
If Sanctum2 still doesn't start, you have an additional problem.
S3TC texture compression is patented and may be missing in open-source drivers such as intel; which may result in missing textures. This can be fixed by installing the libtxc_dxtn library for your distribution.