It's barely a game, more a testbed for ideas and code about space combat (well, the physics of colour and movement anyway) that would form a proper game if more design were added. Think of it as a toy to play with, rather than something that completely defines your goals, though you might want some examples of things to do while learning it:
- Control the display. Your colourwheel is the one that starts in the middle, and can be emphasised by switching on its colour arc display (with the 'a' key). You can change the scale of the picture with the number keys, '1' for most zoomed in, '9' for least, with '2' the starting scale and '3' another reasonable early scale. Your colourwheel can move about or be fixed in the centre of the window while everything else moves around it (switched with the 'c' key). Some objects are shown as pretty baubles, but may be easier on the computer or player as simple circles (switched with 'b' key).
- Learn to move. Colourwheels move like spacecraft, using their engines to accelerate and then coasting in the same direction until something gets in the way, or they accelerate again. The up arrow key accelerates, using blue pixels as fuel, in the direction away from the middle of their blue segment. Left and right arrows increase rotation to left or right, so use of the three arrow keys allows movement anywhere, once you get used to it. The playing area (black) is bounded by inner and outer circles (grey), which moving objects bounce off without being damaged. Using bouncing to go where you want is often cheaper in blue fuel than driving there directly.
- Eat and grow. Colourwheels use the primary coloured pixels to do things, and need to gain more to keep going. The secondary coloured circles are food, which colourwheels eat by colliding with them, so they become segments of the same colour within the colourwheel. The secondary colours are then digested, half into each of the primary colours they contain. So yellow becomes red and green, cyan becomes green and blue, and magenta becomes blue and red. New food appears in random places as old food is eaten, and all food slowly expands until eaten.
- Ram other colourwheels. Other colourwheels compete for food and attack you directly, so you may want to eliminate them, by ramming or shooting missiles at them. Ramming happens whenever two colourwheels collide, with damage to the colour segments where they touch, related to their closing velocity. Green pixels are armour, and take only a quarter as much damage from any attack as other colours do, so keep your green shields towards incoming attacks when possible.
- Shoot missiles at other colourwheels. Missiles use up red pixel ammunition and can be launched with the space bar, aimed at the current target (the one with a flashing halo around it). A new target can be chosen by clicking on it, or by cycling through all possible targets with the tab key, or the nearest target can be selected with the 'l' key. Aiming missiles at moving objects is so difficult that it's usually best to use the computer for the trigonometric calculations: a message in green or red shows whether a missile can currently be launched, depending on relative velocities of yourself and your target. Missiles have limited range and bounce off gray walls, and the target may change course while the missile is in flight, so even when you have a good target lock the missile may still miss for various reasons.
- Raise your score and try to win. Colourwheels score victory points for damaging each other (and lose them for being damaged themselves), and can buy points for green pixels (with the 'v' command). Scores are displayed as each wheel's percentage of the total of all their scores (displaying the list can be toggled with 's' command). A wheel wins if its score reaches 95% of that total.
- Know the enemy colourwheels' tactics. It's far from artificial intelligence, but the other colourwheels take automatic actions when they have an excess of any one primary colour. This can happen very suddenly if they lose a lot of their other colours to ramming or missiles. Too much blue makes them accelerate, too much red makes them fire missiles at you when they can (sounding a long warning siren), too much green makes them buy victory points, and the combination of size and victory points makes them split in two, slowly diverging.
- Know other odds and ends. You can fire missiles manually (with the 'm' key), even in defiance of the computer targetting thinking it's too hard to hit anything that way, but it usually is. P for pause is another handy command key.