It's a new kind of text adventure game played entirely with Twitter interactions using @ replies. You don't even need to follow anyone. It's all done by sending @ replies to a character from Phrenic on Twitter, known as @PhrenicDoll.
All you need to do is tweet the word START to @PhrenicDoll
Then @PhrenicDoll will reply to you. At the end of the tweet are two options in ALL CAPS. Reply with one of those options (your answer doesn't need to be in all caps). You'll get a new tweet until you reach one of the endings (or if stop replying). Make sure you use the exact phrase.
Let's say you made a bad choice in the story and want to "rewind" to a previous decision. Just type the ALL CAPS option and you'll resume the story from that point.
You can also tweet START to @PhrenicDoll at any time to re-start the whole game.
Let's say you start playing on the bus then get to work and can't play anymore. Simply stop replying to @PhrenicDoll (she won't mind). On your bus ride home, you can reply to her latest tweet to resume the story.
To stop playing, simply stop replying to @PhrenicDoll. She only talks to you when you talk to her.
Your interactions with @PhrenicDoll won't be seen by people who follow you unless they are also following @PhrenicDoll, or if they go directly to your profile page.
Yes, once @PhrenicDoll has replied to your tweet, you can delete your tweet. But if you do that, you'll lose the conversation thread in Twitter that allows the whole interaction to read like a story.
You might get lucky once.