A couple of important things:
1. You can play through the game either solo (AI teammates) or in a team of up to 4 friends +1 support player playing through the app. Furthermore, your team can play purely against AI throughout the game, or join player v player which pits teams against each other fighting to complete objectives.
2. There are no sequels planned, the idea is to keep the game going by simply offering loads to do, not sure if there will be dlc.
Its an RPG so expect character customisation, an idea on the offical forums is to have an option for facial capture to render your face in-game, no idea if it will happen or not.