July 14, 2520 AD. The human race was annihilated by the light emitted by the "stone-like object" excavated from the stratum before Christ. Only four crew members belonging to the space cruiser "TETRA" and one robonoid survived in satellite orbit. A year later. The supplies on board are depleted. TETRA is forced to re-enter the atmosphere and begin the fight for human survival. Strategic shooting game There is a chain bonus that keeps increasing the score by continuously defeating the same enemy, a secret bonus generated by defeating enemies in a specific order, and a hidden score item. The key to earning a score is to cover all of these, build an original pattern for strategy, and accurately defeat the target enemy. Stages with various topography such as intricate gaps and moving containers become battlefields, and enemies attack from all directions, up, down, left and right. And 23 bosses await beyond... 6 highly challenging stages await you. Use different weapons that level up by earning points and beat the high score