The only requirements are that you have the .pak and the game in the same folder. I've never heard of this issue before, it sounds like the textures aren't loading properly (RAM/graphics processes) or something caused the game to crash during start-up. The only lead I have is that a couple of users have had issues updating from previous versions through the Itch.io updater.
You can try downloading it again or putting it in a different folder but if that doesn't work, I hope it'll start working again in the future or I'll find out what the issue is.