Spy vs. Spy IV: Spies in Space (cancelled PC game; mid-late 1980s)
The ending of the C64 version of the third game in the series which the fourth game confirmed.
Spy vs. Spy IV: Spies in Space is the cancelled fourth installment of the Spy vs. Spy computer games based on the popular MAD comic strip by Antonio Prohías.
Very little information is known about the title, as it was only confirmed in the third game's ending which shows the spies in a rocket ship launching to space with a text saying "SPIES IN SPACE". That ending was removed in the later computer ports of the game.
It's unknown how much work was done in the game if any.