Game Dimensions

Introduction

When writing a simple game, it helps to know what game you are writing. "Ah, but that's easy," you say. "I'm writing a driving game for mobile." Well, not so fast. Have you consciously decided what you are doing, or do you just have a vague idea? The trick to a successful game jam such as Ludum Dare appears to be laser-like focus on a core idea, because your choices narrow into features that you can implement before the deadline. But what if you have fewer time constraints and you still want to make that game? The design decisions that you make can have a big impact on the shape of the game, yet you may not be aware that you are making them.

Card Games

Take card games. There are 52 cards and 4 suits in a standard pack of cards, yet given these constraints there are many varieties of patience (solitaire) alone. The range expands greatly when you consider other card games and expands even further if you include collectible card games and other games that don't use a standard pack.

Choices in a  Top-Down Driving Game

Let's take a simple top-down driving game for phone and tablet and look at just a few of the decisions that can be made. In most cases, the pieces of the game are constant as there is always the player's car, there are always other cars, the view is always top down, and so on. What makes one game different from another game that uses the same basic pieces are the choices that you make. Here are some of those choices, even before adding in things like theming, power-ups, terrain types, etc.

Steering

How do cars move left and right?

1. Discrete movement. Cars move a lane at a time.
2. Continuous movement. There are no lanes.

How does the player move their car left and right.

1. Swiping left or right.
2. Tapping relative to the screen. Tapping the left of the screen makes the car go left and tapping the right side of the screen makes the car go right.
3. Tapping relative to the car. Tapping to the left of the car makes it go left and tapping to the right of the car makes it go right.
4. Single tap. A single tap makes the car change lane in one direction. Subsequent taps make the car move in that direction until it reaches the edge of the road, at which point the direction changes.
5. Tilting the device. The player tilts the device left or right to steer.

Speed control

How do cars change speed?

1. Cars travel at a fixed speed. You'd probably discard this option without even thinking about it, because it would pretty much rule out racing, but if you weren't making a racing game then it might be appropriate.
2. Cars accelerate up to a maximum speed and stay at that speed until they crash, or go off road, at which point they revert to a minimum speed.
3. Cars accelerate and brake.

How does the player control the speed of their car?

1. The player has no control over the speed of their car. It accelerates, but that's not up to them.
2. The player holds down a virtual accelerator pedal to make the car go faster. The car slows down when the player releases the pedal.
3. The car accelerates by itself, but brakes when the player presses a virtual brake pedal.
4. The car accelerates by itself, but its maximum speed is dictated by the current gear (low / high).
5. The player uses a dial or slider to set the desired speed of the car and the car accelerates or brakes to match that speed.
6. Swiping forward and back. The player swipes forward to accelerate and swipes back to brake.
7. Tilting the device. The player tilts the device forward to accelerate and tilts it back to brake.

Tracks

What sort of track does the car drive on?

1. Fixed circuits. Cars travel round a number of pre-designed circuits.
2. Fixed courses. Cars travel from one end to the other of a pre-designed course.
3. Fixed road data. Cars travel freely on roads, perhaps pulled from Google Maps, or on pre-defined layouts.
4. Random, fixed length courses.
5. Random, endless courses.

Objectives

What does the player have to do to keep playing?

1. Win a race, or place in the top 3 of a race to unlock the next track.
2. Reach the next checkpoint within a time limit.
3. Get as far as possible without crashing.
4. Drive a getaway car and avoid being caught be the cops.
5. Deliver passengers / goods (pizza) in time.
6. Drive a police car and apprehend criminals.

Camera

How the camera follows the car can make or break a driving game. Too close, and you can't see what's going on, or worse, you get motion sick when cornering.

Zoom.

1. The camera is very close to the player's car. This results in the player not seeing a lot of the track, so the camera has to lead the car. This leads to a very immediate style of racing where the player mostly reacts rather than plans.
2. The camera shows a large amount of track, but not all at once.
3. The camera shows all of the track at once. This could work well on tablets, but would rule out most phones.
4. The camera's zoom adapts to the speed of the player's car.

Heading.

1. The camera maintains the same heading as the car so that the car always looks like it is going up.
2. The camera interpolates between its heading and the car's heading. 
3. The camera has a fixed heading.
4. The camera is in a fixed position and adjusts its zoom to act as it it was at a fixed distance from the player's car. This does rather break away from the "top-down" idea, but it is a good compromise between showing all of the track and moving the camera with the player's car.

Replayability

As this is primarily a phone and tablet game, the player needs to feel that they can pick it up for a few minutes at a time, or even a few seconds at a time, and still make progress. How does the game encourage the player to come back time and again? All of the choices below could easily apply to a top-down driving games.

1. Fail fast, fail often. Flappy Bird is a great example of this. You play, you die, you play, you die, and you go right back into playing again with no rigmarole or red tape because there's nothing between you and another game.
2. Progression through a persistent meta-game. In Daddy Was A Thief you play the same game time and again, but your progress in previous games allows you to earn upgrades.
3. Progression through unlocking levels. Desert Golfing is an extreme example with over 3000 levels. It also epitomizes the "play for a few seconds at a time" idea.
4. Multiple competitive elements. Games can have scores for each level, fastest times for each track, awards for completing multiple tracks without crashing, etc.

One Button Racer (zoomed in)

Conclusion

This post was inspired by the idea of bringing One Button Racer to mobile. Different paths through the choices above have led to some very different game concepts, all recognizably top-down driving games, yet all quite different.

When designing a simple game, it can be very helpful to tease out some of the choices that you might be making without knowing it. Write them down and think about what the game would be like if you made different choices.