Kobi’s using RPG Maker MZ. I also have this game, and the tiles are the same in that version.
Are you sure about that?
I know it's not RPG Maker MV, which has a similar file structure. (Dev said so three months ago)
My computer says its file descriprion is nwjs and the original filename was nwjs.exe or nw.exe or something like that, but I have no idea what that is.
For RPG Maker, the file description is game and the original filename is Game.exe according to my computer.
Well, it’s only Game.exe because it’s used as a transfer package. The software used to create the game and the package created aren’t the same. The screenshots Kobi provided have sword marks, which is what the default icon would be like when play-testing RMMZ. For RMMV, it has a castle icon and what not.