While there's a lot to like here, I think there's a bit of a fundamental design problem with this game in that it doesn't respect any kind of grid system. Probably the most egregious issue is that the growth room becomes annoyingly hard to manage the second you get more than 4-5 slaves / goblins in there. When they all pop (mature) at the same time, it becomes a frustrating mess just to try and sort through them all.
I think a better setup would have been for all the rooms to obey a grid system (e.g. the growth room could be a 4x4 size) and for the growth room to have organised slots that fit that grid layout.