GameAction [AppID 0, ActionID 3] : LaunchApp changed task to SiteLicenseSeatCheckout with ""
GameAction [AppID 0, ActionID 3] : LaunchApp changed task to CreatingProcess with ""
GameAction [AppID 0, ActionID 3] : LaunchApp waiting for user response to CreatingProcess ""
GameAction [AppID 0, ActionID 3] : LaunchApp continues with user response "CreatingProcess"
Game update: AppID 0 "Slain: Back From Hell", ProcID 1036, IP 0.0.0.0:0
SpawnProcessInternal: chdir() failed, errno 14
GameAction [AppID 0, ActionID 3] : LaunchApp changed task to Completed with ""
/bin/sh: 1: Syntax error: Unterminated quoted string
>>> Adding process 1036 for game ID 33554432
>>> Adding process 1037 for game ID 33554432
Game removed: AppID 0 "Slain: Back From Hell", ProcID 1036

Desktop file created by gog installer

[Desktop Entry]
Encoding=UTF-8
Value=1.0
Type=Application
Name=Slain: Back From Hell
GenericName=Slain: Back From Hell
Comment=Slain: Back From Hell
Icon=/home/solitude/games/Slain Back From Hell/support/icon.png
Exec="/home/solitude/games/Slain Back From Hell/start.sh"
Categories=Game;
Path=/home/solitude/games/Slain Back From Hell

If i move game to a spaceless path and adjust desktop file it launches normally.