Its not that close. Some things are, and some things aren't. I also see things of limbo in there, but with the vast majority of games out there, how easy is it to have an own style nowadays? Its not a complete clone in the sense that its nearly the same game in terms of levels and so. It has some coincidences, but NightSky has its own unique game meganism, that is not present there. Besides, at the time of NightSky there were other games with a silhouette appearance too.