Based on the idea of a worker placement game with workers that eventually expire, Swarm is a pickup and delivery game in which each player controls a bee hive aiming to be the first to grow so much that it swarms, that is, it sends half of its population elsewhere to form a new hive.
On the game, players take turns activating bees in order to gather honey, recognize the surroundings, organize the hive, make royal syrup, feed the babies and feed the queen (thus making new baby bees or baby drones). After all the bees have been activated, each bee ages (actually, it "weeks", but anyway), becoming more experienced (and thus having more actions to spend), but getting closer to passing away.
When a player with an overpopulated hive feeds one of the baby bees with royal jelly, it will become a new queen bee, thus ending the game at the end of the action phase. As game ends, the swarming happens, with all drones flying to mate with the new queen bee. The player that most influenced the new hive's genes - that is, the player with better fed drones/new queen bee - is the winner