Undertale Has a variety of Choices Leading up to your very own Story. Undertale has an amazing fanbase that streches from theroies to youtube letsplays.
After playing there is millions of theroies and fan games for you to interact with on the internet. Or Start in youtube to uncover the game's Secrets
Or create Fan Art and interact in many google+ Groups
IT ALL STARTS WITH YOUR FIRST PLAYTHROUGH
http://undertale.com/