How do you run them over, you ask? Simple. Use WASD to move your wheelchair. Press and hold <SHIFT> to activate your boosters. Drive over the hippies with your boosters on and watch them explode into glorious red! Running over hippies has never been more fun.
The hippies come in waves. Run over all of the hippies to advance to the next level. You health is restored at the start of the wave.
Source code hosted on GitHub here