What this crack/trainer basically does is freeze the demo timer. Moreover, this trainer provides players with infinite ammo, super speed, and the ability to not reload the weapons. According to its instructions, you can reset the counter by starting the trainer and then pressing Numpad 1 while you are in the menu or playing the demo. Alternatively, you can alt-tab and close the game process (from your Task Manager) while the trainer is still running and then reload the demo.