PS ~~ going thru the upgrade level, the Lvl6 attack power pt seems way off from the Lvl5. The price is double, but the hp is only 22 more extra.

Also, you might consider increase the bonus reward on the Lvl20, as the 1mil will not be enough for the restart upgrade and to cash out some. Unless you don't plan to have your gamers replay.

Besides, can you provide us the total rewards per zone level? I noticed the reward is varied within each lvl of the zone.