a few tips to make your life easier. 1. making more towers is more effective than upgrading. 2. once you can build Treewitzer (ranged tower upgraded with a green stone) you should always start the map with it. 3. spend all your stones for upgrades. start with defence for melees and offence for ranged. save only 1 green stone for each map
gameplay is very decent however the items could be more diversified. but the only thing that made me stop playing was the lengthy downtime for hp regen
Nice tips! Thank you very much :)