Game play:
Each player takes a playing board, feature detector, and marker, then draws a feature card. Only aliens showing this feature live on the player's planet. Each player tries to find out the feature card that the other player drew.
On their turn, a player draws a face-down alien card and asks the other player if that alien lives on that player's planet. If the player says yes, the alien is placed on the first player's planet, if not, it is placed on the outer space area. The first player then crosses off any features that they can rule out on their feature detector, and it is the next player's turn.
Instead of their turn, a player can also guess the other player's secret feature. If they are right, they get a planet card and the round ends; if they are wrong, they lose a turn. At the end of a round, players wipe clean their feature detectors, shuffle the alien and feature cards, draw new feature cards and start another round.
The winner is the player who wins their fifth planet card.
In the advanced rules, two feature cards are drawn, and only aliens showing both features live on that planet, and the game finishes after one round.