· 2 versions exist – easy (early) and hard (later). Starting at mission 9, the easy version has a double ring formation in the center of the Space Warp screen (picture #1); the hard version has a ring and “square” (4 dots – picture #2). The hard version corrects a bug (described below).
· Level skip: On the newer version, while you are in a game, flip the test switch on. If you hit the Player 1 button it will finish that level and go to the next. Nothing unusual happens past level 99, other than the game being very fast!
· Running into a point value (after destroying an enemy) is deadly.
· The mission counter rolls over at 100. The score counter rolls over at 1 million.
· BUG: On the Astro Battles screen, the last two invaders can be slowed down to a crawl if you keep firing rapidly.
· BUG: On the older version, in the Laser Attack screen, kill all the invaders except for one laser invader. Then move to the far left side of the screen and the laser will never hit you. This was fixed in the later version.
· FRYING: Hold down the 1P button while quickly powering the game off and on. You will get thousands of free credits.