Surprised that some people think it's as challenging as they claim. I've been playing for a week, haven't invested any $$$ into the game what so ever and managed to beat the current final stage and have the last girl. (for the time being.) It's not that hard of a game, you may have to wait some to upgrade skills sure but it's not behind a paywall at all. Think before you move. Upgrade your skills, and of course pray to RNGesus to have your back.