Trax (1991) (HAL Laboratory) Nintendo Gameboy
Multi-directional scrolling shooter starring a cute tank!
One firebutton to rotate the turret, one to shoot.
Keypad moves in any direction.
Several power-up weapons can be found (Shot Through, Bomb, 3-way Spread)
The original game (gameboy) is very easy to beat and suffers from slowdown in several occaisions, but it's a very fun game, and it also supports up to 4 players deathmatch game.
I will be lurking in this forum if you have any comments/questions