Tempest

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.

This game was chosen as the first arcade game to have its source code openly documented by enthusiasts of the game. The Tempest Code Project has detailed information about the game. It was coded in 6502 assembly language. The prototypes for this game were called Aliens Vector and Vortex.

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.

First machine Sam and I got together. Beautiful likely home-use machine, have all original documentation for it.