Yes, it currently only supports a restricted ruleset that includes GoL. This ruleset being, specifically, 2-state totalistic automata using the Moore neighborhood. I am planning on adding the capability for multi-state totalistic, and eventually, non-totalistic rules. The rule representation does get complicated, though, so it'll take some time (keep in mind I have to represent the rule in a way that can be passed as a texture to a GLSL frag shader).
You can read more about the ruleset in my blog post. You can also follow this project to get a notification when it is updated, if you like. :)