The Earth was attacked by the aliens and it is in danger! But, if you cooperate with each other, you can save it. Invaders is a cooperative and memory-based game that is played in two phases: the "planning" one where you have to deploy your interceptors based on the aliens that are drawn at every turn the "invasion" one, where you check how well you did in the planning phase (and where you have few chances to correct your mistakes) It contains 5 different difficulty levels, each introducing new material and rules. —description from the designer