On Mars: Alien Invasion is a short story expansion to On Mars made in 4 chapters with 4 different modes of play. The short story is called Alien Invasion and contemplates the following Chapters and modes of play:

• Chapter 1 - Invasion - 1 vs All - 3 to 5 players
• Chapter 2 - Outbreak - Co-Op - 2 to 4 players
• Chapter 3 - Blackout - Co-Op - 2 to 4 players
• Chapter 4 - Monolith - Solo - 1 player