Quite a bit. The Steam version now has a proper structure and objectives. So that means missions and lots more research and a proper end goal. Also the Folk are now a core part of the game. They give you Love which you use for research so you need to keep them happy to keep the love flowing. There's 3 play modes now, Campaign which has all the missions, Creative which is do anything you want and a third mode which has all the objects and buildings unlocked but you still need to manufacture stuff. Of course there's a whole lot more new building types and objects and there's some special big buildings called Wonders which unlock special abilities. There's a lot more changes than this but that's the big stuff. You can check out past posts here on updates but not everything has been listed there https://denki.itch.io/autonauts/devlog