tasuku13 is not i666iky939/anime13master
But yeah, such is a fate of RMXP games. If that battle system really is unique, then it makes sense that the game was "cracked". Otherwise, who's not to say all these resources just exist in the public domain and the two people happen to have used the same things?
Though, of course, in this video, it's too much of a coincidence to believe this wasn't stolen.