Asteroids

Goal of the game

Fly a fighter through an asteroid field. Every rock you hit breaks into two smaller, faster fragments; the smallest ones are pulverised. Clear the space to move on to the next wave, without getting hit.

Controls

• Keyboard: ← → or A D to rotate; ↑ or W to thrust; Space to fire (hold for continuous fire); ↓, S or Shift for hyperspace; P or Esc to pause.
• Touchscreen: the cross rotates (← →), thrusts (↑) and triggers hyperspace (↓); the buttons on the right are for firing and thrust.

Piloting

• The ship keeps its momentum: to brake, turn it around and thrust.
• Space has no edges: whatever leaves one side reappears on the other, your shots included.
• Hyperspace teleports you at random. It saves you from a trap, but nothing guarantees a peaceful arrival; there is then a short cooldown (gauge at the bottom left).
• After a loss, the ship returns to the centre as soon as the way is clear, protected for a moment by a shield.

Points

• Large asteroid: 20; medium: 50; small: 100.
• Large saucer: 200; small saucer: 1,000.
• Wave cleared: bonus of 100 points per wave number.
• An extra ship every 10,000 points. You start with three ships.

About the AI

The large saucer mostly fires at random; the small one aims at your ship along the shortest path across the toroidal space, iteratively computing the meeting point between its projectile and your trajectory. Depending on the level, this anticipation is more or less complete, and an angular error, which shrinks as your score climbs, is added to every shot.