I have been enjoying playing this game. It has given me something to do when bored. It is very addictive I think, lol. As a suggestion though maybe make it where the books can be combined.... maybe give the books a level as they are combined. Merely a suggestion but, it may add convenience for the players
I am most certain that the creator needed 'constructive' criticism here guys: for the couple that had been a bit too harsh, why not try to think if you were the creator and making your first game. Like any artist something helpful, not harsh is what will help. Harshness only leads to people clamming up and not even trying in life. Aside from the rant (SORRY) I think once things are moving properly all will be able to make a better rating of the game
This is a nice little boredom breaker but, I agree with not spartacus. I think some well thought out upgrades and graphics changes would make it reasonably better. I do hope you upgrade this.
 "Idle Raiders"){kind=icon}
 "my first game"){kind=icon}
 "Center Defenders"){kind=icon}
 "Flop Shot MiniGolf"){kind=icon}