Ive defeated the last boss plenty of times and i havent payed for any upgrades or whatever. Granted it too several attempts to figure out the most ideal deck, but thats kinda what gives the game its time played. Yes, it was and is dofficult to beat the fi al boss and even sometimes the third boss. Thats part of the challenge and the rng isnt a game killer like some say. Overall, this is a great game for anyone with the patience to try again and, the understanding to learn.