Destroy each volley of enemies to progress to the next level.
When 50 enemies have escaped, your game is over.
Type 'r' to RESTART the game at any time.
Troubleshooting
If bitmaps do not seem to be updating or loading properly, wiggle your mouse outside your browser window.
Windows 95 users using "auto hide" on your start bar, minimize the start bar before playing as it will interfere with repaints.
If you are still having problems with the level backgrounds not painting completely after following the above two suggestions, feel free to pre-load them here (1, 2, 3, 4).
