If you want use ← ↑ ↓ → and Ctrl as FIRE choose Kempston Joystick.
Keyboard: W = Forward, Q = Pull Back, K = Jump, M = Duck, ENTER = Start, W + ENTER = Speed Up, Q + ENTER = Speed down, P = Joystick/Keyboard (1,2,3,4), O = Players (1,2), I = Skill Level (1,2,3,4), S = Pause