The itch version is an alpha, it's still being heavily developed, and some bugs and crashes may occur. It has about 20x the content of the demo, but it's not complete yet. There are 3 big patches on the roadmap right now: gods in v0.6, endgame content (victory conditions) in 0.7, and graphics mod with Steam release, then some stabilizing with bugfixes, etc, and then we can say it's complete. :)