4 July 2013Gamasutra:
In that game the play primarily centers around completing “dungeons”. To the consumer, a dungeon appears to be a skill challenge, and initially it is. Of course once the customer has had enough time to get comfortable with the idea that this is a skill game the difficulty goes way up and it becomes a money game. What is particularly effective here is that the player has to go through several waves of battles in a dungeon, with rewards given after each wave. The last wave is a “boss battle” where the difficulty becomes massive and if the player is in the recommended dungeon for them then they typically fail here. They are then told that all of the rewards from the previous waves are going to be lost, in addition to the stamina used to enter the dungeon (this can be 4 or more real hours of time worth of stamina).
At this point the user must choose to either spend about $1 or lose their rewards, lose their stamina (which they could get back for another $1), and lose their progress. To the brain this is not just a loss of time.
These strategies aren’t particularly complicated or technical, they are just well refined pieces of psychological persuasion. In particular, the “reward removal” ploy quoted above comes straight from the minds of the arcade game cabinet makers. It’s “insert coin to continue” in a different presentation. You invest so much time into a game that you’d rather pay a little to keep going, than forfeit your progress.1
1 Imagine a freemium word processor where you have to pay to save your file.