He doesn't compress the images much but the majority of the size is the animations. He uses still frames and has renpy rapidly change between them rather than covert the image series to a video this makes what would be a 500kb-1mb video into a 20mb+ image series for every animation/angle.I've only seen a couple of others with that kind of file size or larger, and they were significantly bigger games in terms of content. Are the visual files in 4k or something?