Thanks for awesome game.
But it's pretty easy.
So i have a few thoughts how to expand gameplay further.
Now fire bombarding is too op and if player use tab often he can track newborn graveyard and burn them before construction end.
That'll be really good if sometimes happens random invasion. Just 10-25 sketons/zombie if player handle too well.
And i have other idea but really dont know how well it fit.
When i get boored from bombarding i decide to make drop squad of golems(just drop 5 of them with 0* spell directly on graveyard). And its work pretty well.
So i think its can be good to rise cost of stone golems and buff them or make higher tier: iron golems ! Reduce bomb spell efficiency against high lvl buildings (1200+) and add new spell order: all golems get together and attack this zone.
This give dark force chances to make 2-4 high lvl base before player get hight lvl golems to clean them, and player still can burn low lvl graveyard so he be able to progress.