Timeslip

The author of the original version (Jon Williams) released a fixed and updated version for the 5200/Atari 8 bit platforms in 2020, known as "Timeslip 2020".

On a distant planet, 36 Time Orbs have been placed in three zones and in 24 hours time the planet will be destroyed unless all the Orbs are destroyed. You have been sent to the planet to save it by controlling three different vehicles and crafts in the three zones and they are the planets surface, underground caverns and underwater. The game is a side view horizontal scrolling shooter where the screen is split into three parts showing all three vehicles and crafts and they are a spacefighter for the surface, jet-pack for the underground caverns and a mini-sub for underwater. As the game starts you select which one to control and you move from right to left destroying all aliens, vehicles, weapons and the orbs as the main clock counts to zero.