You control a yellow crab-shaped shooter that travels along the outside rim of a 3-dimensional tunnel, shooting enemies down the alleys of the tunnel while avoiding any coming down the alleys. The tunnel takes on many different forms, and the shooter has a special “superzapper” that enables it to kill all enemies present in the tunnel.
You are given a vanishing-point perspective from the top, looking down into a geometric shape. The shapes vary from a line, to a triangle, to a circle, to more complex shapes. Enemies enter from the bottom and work their way up towards the top. Collision with an enemy or an enemy’s shot is fatal.
A level is cleared when all the enemies have been destroyed, or the only enemies left are the red shooters that have reached the top of the tunnel. When proceeding to the next level, shoot and destroy, or avoid, the green spikes that are left over, as a collision with them is fatal.
The superzapper will destroy all the enemies on screen the first time it is used. The second time has a much more limited effect. The superzapper will not work a third time. However, the superzapper recharges itself at the start of each new level. The final levels of the game are the green, which begin at level 81, and repeat thereafter with no increase in difficulty.
TRICK: On a level that is not a fully enclosed shape, you can often sit at one of the far ends, and when an approaching enemy is right next to you, hold down your fire button, and they will be destroyed.
TRICK: Get a score in the form of XXYYZZ, where XX > 16, 29 < YY < 60, and ZZ is a code. Some codes are: 01 - Test mode. 06, 11, 12 - 40 free games. 46 - Start at any level you like up to level 81. In the test mode, you can zero the high score table and examine the game parameters, but not modify them. BUG: Scores beyond 999999 are not possible, as the score will roll-over to 000000.