This is a lot of years old, but I figured out everything for every level in the demo.
You do have to be very aware of these quick time events, otherwise you might suck.
Level 1: numpad 3 is grab, you press it. Next is the down arrow key, press it quickly and you win the level.
Level 2: The KICK button for level 2 is numpad 2. Next action is numpad 3 (grab). Last action is right arrow key.
Bonus Level, dodge the bullets: Right arrow key, up arrow key, down arrow key and numpad 2.
Level 3: numpad 1 (punch), numpad 2 (kick), numpad 3 (grab), this one is really quick, last is numpad 2.
Level 4: numpad 2, numpad 2 again, and numpad 3.
Bonus Level, mirror mode: Up arrow (down arrow), Down arrow (up arrow). The last one is not opposite, numpad 1 (punch).
This is the whole walkthrough for you to beat the whole demo, I hoped this helped you get over your rage.