You can finish with only Ballistas - there's no reason to buy any other kind of turret, apart from the pearl wins - but if you don't need the other turrets, you don't need those extra pearls.
Thanks, you were right on both counts! We're going to rework the balance so every tower has a job and no single one can carry the campaign, and make the Endless Tide adapt to your build so it actually gets hard. Thanks a lot for playing and for writing this!
