Written by me, Rob Chavers. This is my first flash program and is still under construction.
  How to play Asteroids^TM
The object of the game is to destroy as many asteroids as possible and keep your ship in space as long as possible.
Use your keyboard controls to maneuver your ship through space and shoot photon torpedoes at the asteroids.

Controls

1	Begin playing a one-player game
2	Begin playing a two-player game
Right Arrow	Rotate clockwise
Left Arrow	Rotate counter-clockwise
Up Arrow	Thrust forward
Down Arrow	Jump into hyperspace
Space Bar or Ctrl	Fire photon torpedoes
P	Pause / Resume the game
S	Sound On / Sound Off
D	Change Detail (Low, Medium, High)

Note: you *must* click the game window before any keypress will work.

How To Play

The ship moves and fires only in the direction it's pointed. Press and release the Fire button as fast as possible to have up to four torpedoes in action at one time.

When an asteroid is hit, it may break up into smaller boulders, or it may be completely pulverized.

Use the Down Arrow to jump into hyperspace, which makes your spaceship disappear and reappear at some other place on the screen. Hyperspace is helpful as a quick getaway when an asteroid or boulder is headed toward your spaceship, but it may also be dangerous if your spaceship reappears in the path of an oncoming rock--or even in the exact same space.

Scoring

Points are determined by the size of the asteroid boulders. Since the smaller boulders are harder to hit, they're worth more points. You start with three spaceships each game. You earn an extra spaceship for every 10,000 points you score.

Points are scored as follows:
Small asteroids	= 100 points
Medium asteroids	= 50 points
Large asteroids	= 20 points

Gaming Tips

After playing Asteroids several times you'll discover which techniques work best for you.
Here are some that the space cadets at Atari found most helpful.

• When the screen becomes clear of asteroids (just before a new group of large asteroids appears), try to avoid placing your spaceship close to the right or left edge of the screen. New asteroids almost always begin from these edges.
  
  
• It is often helpful to remain in the center of the screen throughout the game, aiming your spaceship right or left in a circular motion.
  
  
• If you're close to earning an extra ship, and your spaceship is about to crash, you may want to cause your spaceship to collide with a small asteroid. You'll earn points even if you crash, and this may be just enough points to earn that extra ship.
  
  
• Try to hit the faster and smaller asteroid boulders. This will give you more protection and more points.
  
  
• If the game is slow on your computer, try turning off the sound and/or setting the detail to "LOW".

Note: The text above was taken from "gamers.com" I changed the formatting and layout style to fit my Asteroids game.