Pilot your ship around the spiral to the planet's core. Reach the core and advance to the next level. Complete each level quickly to maximize points. But, be careful! Touch the wall and you lose a life. You get 3 lives to start and 1 additional life per level. Even numbered levels have atmospheric drag (indicated by gray background in the text window) and odd are in vacuum (indicated by black background). Gravity increases every two levels, starting at zero. Play through all 8 levels to complete the mission.  Controls: up to thrust, back to flip, left/right to rotate. Play on the Altirra emulator (800XL) in NTSC video.