Unlocking game content based on amounts of collaborative gameplay

A gaming system for rewarding users of an online game based on cooperative gameplay among multiple users, the gaming system comprising:

• a memory;
• and
• game server, the game server comprising:
• one or more processors configured by machine-readable instructions to:
• determine a first amount of cooperative gameplay engaged in by a first group of users, wherein the first amount of cooperative gameplay is based on a first amount of time spent by the first group of users during the cooperative gameplay in the online game;
• determine a first reward, wherein determination of the first reward is based on the first amount of cooperative gameplay without regard to whether the first group of users is successful in achieving any particular game objectives;
• and
• reward the first group of users by making the first reward made available to the first group of users.