• Tap or click the ground to walk there; hold to steer
• Tap a zombie to go after it and keep attacking
• WASD also move
• Shift, C or the stance button: sneak on / off
• 1–4, Tab, or tap the list
• Q E turn the view
• Wheel zooms
• V senses overlay
• X see-through outlines
• R new level

A knife in the back of a zombie that has not seen you kills it in one, and quietly. Anything else, and the noise brings the neighbours.