No man, its a bug. Traded max health for money and get 0 max health I think (from rnd free buy). And then, when % is calculating - dividing by zero gives nan in hp bar ui (NaN). (I buy rnd for free, then close shop and health become "nan", then loose)
Game is pretty nice btw. But lack of different weapons and strategies, At the atart at least, im only run 2 times.