🚀 Asteroids

How to play

You fly a ship through an open field of drifting rocks. The ship has no brakes: thrust adds velocity and friction bleeds it off slowly, so you are always coasting. Shooting a large rock breaks it into two smaller ones and only the smallest is destroyed outright. Every screen edge wraps, for you, your bullets and the rocks. Clearing the field spawns a new wave, and a collision costs one of your three ships.

• Left and Right arrow keys — rotate the ship, 0.05 radians per frame while held.
• Arrow Up — fire the engine in whatever direction the nose is pointing.
• Space — shoot, limited to one bullet every 250 milliseconds. It also starts the game when idle.
• Start button — begin a run or restart after a game over.

Scoring

A rock pays 100 divided by its size, rounded: 33 for a large one, 50 for a medium and 100 for a small. Breaking a large rock all the way down therefore pays 533 in total against 33 for the first hit alone. When the field is empty a new wave arrives with 4 rocks plus one more for every 300 points scored. After a collision you respawn in the centre with 180 frames of invincibility, shown as a flashing ship.

Tips

• Thrust in short taps. Friction removes only 2% of your speed per frame, so a long burn leaves you drifting fast for a long time.
• Break rocks down to the smallest size before starting the next one. The fragments carry almost all the points.
• Bullets wrap and live for 60 frames, so a shot fired off one edge can hit a rock that has come round the other side.
• Use the respawn invincibility to reposition rather than to attack. It is the only free movement you get.

Frequently asked questions