You can make as much as 3 stars in each phase, and there are 88 to get in total amount. The number of stars you make depends exactly how well you perform in regards to stopping enemies and keeping your main Hero at complete strength. You're most likely to make just one to 2 stars per phase if any enemies slip with. Supplied you have actually sufficient charges left in your meter though, you can retry the phase once again once you have even more resources and characters offered - hence assuring that 3rd star.