Downhill and hill-climb racers

Add a gradient to a road and the car's behaviour changes. Uphill sections demand power and traction. Downhill sections add speed without a throttle, and the brakes start to work harder than usual.

What a slope does to a car

• Weight transfer. Going uphill moves weight to the rear, which can lift the front end. Going downhill moves it forward and can overload the front tyres.
• Momentum. A downhill stretch lets speed build quickly. Brake before the steep part, not on it.
• Crests. A car can leave the ground at the top of a hill. Landing with the wheels straight keeps it stable.

Hill-climb games

Hill Climb Racing from Fingersoft was first released for Android on 22 September 2012. It is a 2D physics-based game on hilly terrain. The player has only gas and brake controls, drives as far as possible and manages a limited fuel supply that is refilled by collecting gas cans or batteries on the course.

Open worlds with real terrain

The original Test Drive Unlimited (Eden Games, Atari; 2006) modelled roads on satellite images of Oʻahu, with more than 1,000 miles of roads and terrain that includes rain forests, mountains, sandy beaches and urban areas.

Technique

• On steep descents, use a lower gear so engine braking takes some load off the brakes.
• In 2D physics games, gas and brake often also tilt the vehicle in the air. A light touch controls the landing angle.
• Keep the throttle smooth on climbs. Wheelspin loses momentum.
• Look over the crest and plan the next section before you reach the top.