Have you tried this one? http://moodle.org/mod/data/view.php?rid=888 It is a plugin for a free online authoring tool called myUdutu. They are a private company that spun off from Royal Roads University a couple of years ago.
Most of the screen templates allow you to "jump" to another screen in the course, or else add a new one you create on the fly, dependant upon the choices made by the learner. So its easy to build several kinds of scenarios or simulations.
You can build a simple scenario where all roads lead to the same conclusion, or a more gamelike one with a variety of outcomes, etc.
One thing to watch for is that when you add a "scenario", which is just a type of container for the screens you'll be including, then the course navigation is turned off by default, so that users have to progress through the simulation and can't jump outside it. So if you add the container but no screens that "jump" back out of it, then when you preview your course the navigation buttons are inexplicably greyed out.
It's worth a try. The tool is free to Moodle users.