The only things I am skeptical about in systema is hypnosis used to make people fall down. That aspect of systema confuses me. ROSS, kadochnikov systema, homo ludens, Ryabko Systema, kaizentao, systema siberian cossack systema are different takes on systema. Homo Ludens is pretty cool. One of my classmates in college used to take classes in it. It is mma mixed with systema.