Unzip the 'DiacrisisDLC' folder and run 'DiacrisisDLC.exe'.
These are the controls for the DLC 'Lost in Hell':
ASWD - Movement
SPACEBAR/Mouse - to shoot
E - Action
N - to jump
R - to reload
Q - to melee weapon
On Main Menu only the ''New Game'' and ''Quit'' buttons are working.
Press Alt+F4 to QUIT. (No Pause menu installed)