The idea behind just a GF is to create a girl that would do anything you ask her. the project is in the early stages, requests from supporters have come in a wide range from just holding hands to cuckolding the player while electrocuting him. So what would you make her do?
In order for you to be able to install this game, you need to enable (allow) installation of applications from unknown sources (Unknown sources) in the phone settings. Usually this item is in the Security section