Linear Bounded Phenogram is a Steins;Gate spin-off. It's not a love spin-off. It tries to be serious. Its tryings are not that good.
Phenogram is a collection of some stories from different perspectives. These stories are very different. Some will make you cry, some will make laugh, some will confuse you. They mostly are non-canon. Their purpose is to tell more about characters' personalities. The game is created to entertain S;G fans. But it's easy to drop this spin-off. It's true that here you have a chance to return to that lab and see other scenarios with your favourite characters. But some of the stories are just bad. Don't get me wrong -- there are some very interesting ones. Moreover, you can read these stories in any particular order separately.
Mind you, that there is not official English translation. There is a YouTube walkthrough in English and an English patch for the fan-ported version on PC.