I ran the game directory through a freshly installed clamAV virusscanner, and it reported all files to be safe.
I compared the game directory with that of other RPG Maker games that I have on my computer, and I did find some unusual things there, like several .js, .json and .webm files. The .png's in the img directory do not have the structure of .png files (my picture viewer couldn't make sense of them), but neither do they have any ELF structure, so they're not Linux executables or dynamic libraries.
So, albeit unusual, the game appears to be safe.