This is all kinda similar to what Sintax did - quite a few of their games seem to have been built on top of Harvest Moon, but I have no idea if they actually stole anything from that game..
IIRC other Sintax games contain parts of Bomberman Max, and one of the King of Fighters games too (the latter is at least somewhat understandable, since they ripped off KOF 95's soundtrack in a few of their games)