You can find details of the original ZX Spectrum game on Wikipedia. For the latest news, visit my blog. Here are the Android specific controls for Chaos.
You can play a javascript version of Chaos here or download for Game Boy Advance and Nintendo DS platforms.

Select the number of players. Press the left and right arrows next to the number of players to remove or add a player. Press Human/Computer to cycle through the computer player's level or change to another human player. Press the player name to edit the name. Press to the left or right of the the wizard's icon to change the colour or graphic.

After choosing players, you can select a spell to cast, examine the spells or examine the board.

If you choose one of the options, pressing the back button will return you to this selection menu. If you choose to quit, then you will be returned to the splash screen. Be careful doing this when playing against other human players, they may not like it if you were losing.

When you select a spell, if it is a creature you can choose if it is an illusion or not. Illusions will always be cast, but can be disbelieved by an opponent. To choose an illusion, either press down on the trackball or press the "YES" part of the screen. To select a real creature, press the back button or touch on the "NO" part of the text.

Once all human players have chosen their spells, the casting round begins. Cast a spell by touching the target square twice. Once to select the square, then again to cast the spell. To stop casting a spell, either press the back button or touch the END in the lower right corner of the screen.

You cannot cast a spell outside its cast range, and some spells (like Magic Wood) are cast automatically for you.

Once the casting round is over, you begin the movement round. Here you can attack other wizards and creatures by moving your creatures or wizard on top of the opponent's squares. The chance of a creature defeating another is determined by the attack and defence of the fighters and a random factor.

To move, first touch the creature to move then touch the same square again to start the movement. Touching a square to move to will move the cursor there, then touching again will complete the movement. To end the movement round, touch the END marker in the lower right corner.

The winner of the game is the last wizard standing!