Overview
Intruder is a solitaire science fiction microgame published in 1980 by Task Force Games in which a rapidly maturing alien roams a space station, ambushing and killing crew members.
Description
Intruder is a solitaire game based on the movie Alien. A young alien life form has escaped from the labs of the space station Prometheus, and hunts members of the crew as it matures and gains new abilities, moving randomly each turn. The player controls the crew working to find the alien and either capture it when it is young, or kill it in its later life stages before crew losses become unacceptable. If all else fails, the crew can initiate a self-destruct sequence to destroy the Prometheus while escaping by shuttle; however, there is a chance that the alien will also escape by stowing away on one of the shuttles.
Gameplay
The game map shows the various areas and corridors of the Prometheus with weapons, lab animals, dummy counters and the alien in various locations. The alien and dummy counters are placed facedown and are all moved randomly. The player does not know if a human has encountered the alien or a dummy counter until it is flipped over.
The sequence of play in each turn is:
Movement of alien: Facedown counters (one of which is the alien) are moved randomly
Interaction phase: Crew members can investigate facedown counters to try to determine the location of the alien. Combat may ensue.
Panic phase: If a crew member is killed, all crew members retreat to the command module and the facedown counters are again moved randomly, hiding the new location of the alien.
Metamorphosis phase: A die is rolled to see if the alien matures and gains new abilities.
Movement phase: the crew can move to search for the alien or reach caches of weapons or technology. If they reach a facedown counter, interaction combat with the alien may result.
Self destruct advances: If the self-destruct sequence has been initiated, the sequence advances by one step.
From Wikipedia (CC BY-SA 4.0).