The game is being released as set of standalone campaigns that can be played in any order. The Prologue is the base of the game, which contains 2 full missions, and will be permanently free on the games release.
The first campaign, Alien Myths, will be available for purchase the same day. It contains new characters and missions with a story that will continue to build on the games world.
There is a total of 4 campaigns currently announced and they are designed to be playable in any order.

The game is a short campaign based co-op shooter that has multiple missions linked together. It has a 4v1 game mode that puts your team against a random online opponent who will also be using one of the games playable characters while interfering in your missions as you play.