You are absolutely correct. I mean at first game engine need to run.That first step is only needed for RPGMaker VX games, which this is not. Most to all of the RPGMaker games that come out now are either RPGMaker MV or RPGMaker MZ, neither of which have a separate install to play games. Older RPGMaker game engines (95, 2000, 2003, XP, VX, and VX Ace) had what you're referring to, which is a set of general files that were able to be installed only once instead of being packaged with every game (that's the RPGMaker (engine suffix) RTP). Each engine suffix and language release had an entirely separate RTP as well, so a VX game can't use the VX ace RTP.