Joystiq reports that the MMO previously known as Marvel Universe Online will be known henceforth as Marvel Heroes. The news was announced by Gazillion Entertainment, who is the developer and publisher behind the free-to-play, browser-based MMO title. The game will be aimed at a more mature audience than Super Hero Squad Online, another MMO title operated by Gazillion Entertainment, which is also based on the Marvel license. No official release date for Marvel Heroes has been confirmed as of yet.