There are limited animations (that have gotten better with time. I'll have to go back and update the earlier ones at some point) and almost 2400 images in the game.
What you're seeing in other games are developers who somehow think that they can't make a quality game if they don't put uncompressed PNG files in it. They either seem to think that high file size is a sign of excellence or that compressing images will make them look bad. Both conclusions would be wrong, but what can I do? I suspect this is a problem with adult game development in particular because there are so many devs here that haven't done any other game development before making their first adult game, so they don't really know what to expect or do.
I compress the images in this game to JPGs at the second highest quality level available to me. Unless you zoom in and directly compare the uncompressed PNG with the JPGs, you would never be able to tell the difference, yet it saves a ton of space.