Nice game. Still a bit buggy, it crashes a lot when someone starts messing with the books (had to replay it again and it crashed again when someone messed with the books). Also as someone else said, the red dot for the upgrades get stuck. Numbers also don't make sense really, someone paying you 3 billion for a book and a bookshelf costing 3 billion... you just have to wait until it gives you enough money to buy upgrades or bookshelves and not really think about the money scale too much.
Still, I'm sure those issues can be fixed, it's a really fun and cozy little game.