All Star Tower Defense follows a well-tested formula. You aim to stop the waves of increasingly difficult enemies and earn Gems to purchase better units as you go. The crazy number of available units made my head spin, and I already accepted I would never unlock everything. Then, I heard...
and after that, I played Infinite Mode to reach level 40 quickly and redeem the remaining codes. If you are like me and like to play tower defense games, I advise you to take a peek at ourTower Defense Simulator (TDS) codesarticle and get some freebies for that game as well!