Ark Nova and Terraforming Mars occupy similar territory — long engine-building games where you are building a specialized engine from cards while advancing multiple tracks — but they feel different in ways that are hard to articulate until you have played both extensively. Ark Nova's appeal maps are more interactive, creating constant tension between what you want to do and what the geography demands. The appeal vs conservation scoring duality creates a different kind of race.

Terraforming Mars has more cards, which creates more variety across sessions. Ark Nova has more interesting animal placement puzzles, which creates more engagement with the physical board. My preference shifts based on group composition — experienced heavy euro players tend to prefer Ark Nova; players who enjoy campaign-style narrative prefer Terraforming Mars.

Both are genuinely excellent. The debate is a false binary. Own both if you can.