A few tips & tricks:
Just click the speach bubbles to take the order if you don?t want to wait. That way you can guide which customer you want to level up a little faster.
Mouse over the customers to see their information.
And also mouse over the items on the left to see their information in the little screen on the right.
Only the star upgrades are transferred when you reset the game, not the manual ones.
And last but not least: Don?t overprice your items. Keep an eye on your customers money before you upgrade an items worth. And remember to check the upgrades pages to see if a good upgrade is available there before you upgrade something manually.
Strategy games
