I too find it hard to get past 3rd wave, usually Gold or Stone is in short supply by then.
If there were Gold mines added it might help the flow of the game and slightly more stone from mining, maybe horse and cart option to speed up the re-supply.
Would be nice to see rolling green hills in places, raise some areas slightly.
Great game though, a real challenge to play.
Thanks for this game, Respondi at Respondi433 Youtube Channel