I Can upgrade at a similar pace on mobile. I just click really fast both of the paths but make sure the actual path i wanna upgrade gets upgraded faster.
391 views in 14 hours? You rose up! Btw, can u tell me on how to beat expert? Just tell the towers and I don't need the Strat, I just need the towers. Cuz, I'm going to learn with those towers u pick to beat expert.