SETI vs Terraforming Mars: Which One Wins?

SETI puts you in charge of a space agency racing to make first contact, and the to-do list feels like real science fiction homework. You scan the sky, collect data, launch probes, land them on moons, and pull alien signals out of the noise. The engine runs on multi-use cards, and I love this bit: every card can be a free action, a main action, or tucked away for income, so almost nothing in your hand is dead weight. The solar system itself rotates, which turns probe launches into a genuine timing puzzle, and there's a mid-game alien discovery that flips the table in the best way. Fair warning though, the opening rounds are cash-starved and slow. The game only catches fire once your engine wakes up.

Terraforming Mars is the sprawlier beast. You're playing cards, over 200 of them, and each one bolts another part onto your economy while nudging Mars toward habitable. Raise the temperature, drop in oceans, seed oxygen. Every action feels like it's actually changing the planet, which is why this game has held its reputation since 2016. One reviewer put 20 games in and said no two felt the same. The trade-off is the table experience: a heavy hand of cards invites analysis paralysis, an early leader can snowball, and those little plastic resource cubes slide everywhere the moment someone bumps the table. The design is gorgeous. The components, honestly, are not.

Neither of these is a gateway game, so plan on a real teach either way. Terraforming Mars is the heavier of the two on paper, and it earns that label mostly through sheer volume: a huge card pool, a full economy to track, and a two-hour runtime that punishes anyone hoping for something light and quick. It rewards patience, and first-timers usually spend a whole game just learning what a good engine even looks like.

SETI sits a notch lower at medium-heavy, and it comes with excellent player aids, which makes the first game friendlier than you'd expect. The tricky part isn't the rules, it's the pacing. New players start cash-starved with few good options, so warn your table that the first couple of rounds feel slow on purpose. Once they've seen the engine spin up and the alien discovery land, it clicks. If your group is newer to heavy euros, SETI is the gentler on-ramp. If they already speak fluent engine-builder, Terraforming Mars won't scare them.

Terraforming Mars is the replayability champion here, and it isn't close. Over 200 project cards and 12 corporations means the variety is genuinely huge, and it sits at number nine on BoardGameGeek for a reason. Player count matters though: two-player games drag, five-player games end before your engine really sings, and three or four is the sweet spot. Grab a playmat or some baggies for the cubes and the box stops mattering.

SETI holds up well across plays too, and the resource puzzle stays interesting, but there's a ceiling: only five alien species means you'll see repeats fast. Its player count story is basically the mirror image of Mars. Two is fast and tight, three is the sweet spot, and four is where downtime balloons and it drifts toward multiplayer solitaire. It also plays lovely solo, which is a quiet point in its favor. So count your usual table before you count anything else.