General optimisation across the board, particularly for late-game saves.
Altered balance of wave spawning. Let's see if you can survive this new format!
Reverted the save system to a system we have in other versions. So when the game saves now it will temporarily freeze while saving (intentional). This should fix most of the bad bugs that were caused by save corruption. If you've experienced a save corruption before you'll have to start a new game with this new patch. You can start from the map at least so you won't have to restart on land one.
Various smaller fixes as a result of the save change which includes: Ballista not firing, Builders not building, and Farmers not farming
Fixed that parts of the background wall upon upgrading the castle would not appear.
Payment system was partially redone, should be faster and a little bit more accurate.