SMR-CNN

i agree with RCk, maybe defense and attack should not be touch, but yes you could buy for xx amount of days more % of exp and cash, or even turns.

i agree with achievements, i say if u reach ach 1 u get 40 turns, if u reach ach2 u get 10% more money for the next 2 days, and so on with exp, defence, attack rate, etc.

well i agree with this, not with ammount. I've been playing other games, ppl were used to spend like 20 USD per month every 2 months. I dont know, may be with 20 USD u could buy certain upgrades, like 7 days of extra defence, 7 days of double turns, 7 days of 200% more cash, 7 days of 200% more exp,...