$ sudo apt-get install libsdl2-2.0-0
Reading package lists... Done
Building dependency tree
Reading state information... Done
libsdl2-2.0-0 is already the newest version.[…]
0 upgraded, 0 newly installed, 0 to remove […]
~/TheSimsOnline/drive_c/Program Files/Maxis$ mono FreeSO.exe
[ERROR] FATAL UNHANDLED EXCEPTION: System.DllNotFoundException: SDL2.dll
at (wrapper managed-to-native) Sdl:GetVersion (Sdl/Version&)
at Microsoft.Xna.Framework.SdlGamePlatform..ctor (Microsoft.Xna.Framework.Game game) [0x00000] in <filename unknown>:0
at Microsoft.Xna.Framework.GamePlatform.PlatformCreate (Microsoft.Xna.Framework.Game game) [0x00000] in <filename unknown>:0
at Microsoft.Xna.Framework.Game..ctor () [0x00000] in <filename unknown>:0
at FSO.Common.Rendering.Framework.Game..ctor () [0x00000] in <filename unknown>:0
at FSO.Client.TSOGame..ctor () [0x00000] in <filename unknown>:0
at FSO.Client.GameStartProxy.Start (Boolean useDX) [0x00000] in <filename unknown>:0
at FSO.Client.Program.Main (System.String[] args) [0x00000] in <filename unknown>:0