Games like The Mars Agenda
Games like The Mars Agenda include Heavenly Bodies, Outer Wilds, LIMBO, Baba Is You, and Never Alone (Kisima Ingitchuna). We matched them by the tags players give The Mars Agenda on Steam (Indie, Puzzle, Space, Local Co-Op, and Difficult): closest matches first, and among equally close ones the better-known games.

Heavenly Bodies
Shared: Space · Local Co-Op · Puzzle

Outer Wilds
Shared: Space · Puzzle · Atmospheric

LIMBO
Shared: Indie · Puzzle · Atmospheric

Baba Is You
Shared: Indie · Puzzle · Difficult

Never Alone (Kisima Ingitchuna)
Shared: Indie · Local Co-Op · Atmospheric

The Binding of Isaac: Rebirth
Shared: Indie · Difficult · Local Co-Op

Brothers - A Tale of Two Sons
Shared: Indie · Atmospheric · Puzzle

Kerbal Space Program
Shared: Space · Science · Indie

Return of the Obra Dinn
Shared: Puzzle · Indie · Atmospheric

Observation
Shared: Indie · Space · Puzzle

Defy Gravity Extended
Shared: Indie · Puzzle · Space

The Witness
Shared: Puzzle · Indie · Atmospheric

Deliver Us The Moon
Shared: Indie · Space · Puzzle

Cuphead
Shared: Difficult · Local Co-Op · Indie

SpaceChem
Shared: Puzzle · Indie · Difficult

Hollow Knight: Silksong
Shared: Indie · Difficult · Atmospheric

Rain World
Shared: Indie · Difficult · Atmospheric

COCOON
Shared: Puzzle · Indie · Atmospheric

Firework
Shared: Indie · Puzzle · Atmospheric

BADLAND: Game of the Year Edition
Shared: Indie · Local Co-Op · Puzzle

Antichamber
Shared: Puzzle · Indie · Difficult

Waveform
Shared: Indie · Puzzle · Space

FTL: Faster Than Light
Shared: Space · Indie · Difficult

Gorogoa
Shared: Puzzle · Indie · Atmospheric