Run Trine 1 on Linux with dual screen. Turns off one screen to avoid picture stretching. Turns on screen as soon as you exit the game.

trine-bin

#!/bin/bash

# Do some magic here

echo "Turn OFF Laptop screen"
xrandr --output eDP-1-1 --off

if [ `uname -m` == x86_64 ] ; then
	./trine-bin64 $*
else
	./trine-bin32 $*
fi

echo "Turn ON Laptop screen"
xrandr --output eDP-1-1 --auto
xrandr --output eDP-1-1 --left-of HDMI-1-1