Game completely halts around level 60 24/2/5

Game was fun and easy to get into, but around level 60 the game will completely halt your progress, without any kind of hints how to beat levels, other than to level up your minis (which does not help at all). The goal is obviously to get you to spend money at that point, so just be aware that’s when the honeymoon ends and the free-to-play pain will begin.