Hi all,
I've been following Choose Your Story, infinite-Story and FF Project and Chronicles for a number of years, and about two or so years ago came across a game called Fallen London.
The creators of that game now have a story game creation engine just like the others, but this engine gets updated quite a lot almost daily, creators can inject living stories into their stories which makes NPCs come alive with timed events and other things, not to mention basic things like stat based systems and whatnot. Fallen London has the most content of course, but I personally prefer the other created stories because I'm not a huge fan of that writing, but I like the system itself. Games that I think worth checking out and have good tutorials for playing them would have to be Zero Summer,
http://zerosummer.storynexus.com
and Orchestra demonstrates that this sytem can indeed have combat encounters. Fallen London doesn't have all that much combat, but Orchestra and Zero Summer has some. There's also a space game Mailstrom that seems worth checking out, and at least two long fantasy games. Plus you can create your own too.
Check out Story Nexus at
http://storynexus.com
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