Don't underestimate the Detonate spell. With the upgrade to get brains back from your zombies and the fact that your zombies drop bones when they die, it can be a nice little shot of profit for the next level to pop all your zombies right at the end.
Great game so far.
My top three things I would like to see would be:
-Passive Base Upgrades: Things like healing stations that up the passive regen in base, a tavern that if you keep Raiders in base for a bit they get a bonus, that sort of thing. Stuff that I can spend my gold on that adds both cosmetic and functional things to the rather bland base. There is only so much time I can stare at my Raiders in their bleak grey room with only two pots in the back before I feel horrible because I'm making them live there or something.
-Some sort of control over the Raiders: Some kind of means in which I can influence how my guys fight, even only minor. The times I would have won a raid but didn't because my healers healed the archer with a booboo over the fighter redecorating the dungeon with bodily fluids can't be counted any more.
-The ability to go back and upgrade farming areas to reward more at higher tiers.
 "Incremancer"){kind=icon}
 "Idle Raiders"){kind=icon}