Ok, here's my impression of the game after only playing a couple hours:
Building is a bit more like a puzzle game, you gotta design your mansion from the start with the goal of proper horror movie killing. From watching Let's Plays you'd think it's a groovy idea to just cram your brain-chopping kitchen table right next to the front door and just rush victims the second they arrive into your house. That's just terrible, don't do it.
You want to funnel your victims in a linear fashion, and one by one pull the victims with revolving wall traps. Add a couple distractions (TV, bookshelf) in the path if the victims are rushing in too fast. Only after these starting rooms begin building the actual minion quarters. What I did was arrange 4 rooms (in the last one I put my writing desk because why not) in a 2x2 configuration, with the doors going thru them in a C-shape. This may or may not be optimal for traps, I dunno.
I haven't got very far, so just basic victims for me, but eventually you want to replace some revolving traps, such as making the first one the Virgin trap and somehow keep the virgin busy so you can kill him at the end. I don't think the order of the other victims matters, but definitely isolate them with lots more revolving walls. You can kill them by hand or using elaborate conveyor belts leading to massacre machines of some kind, I guess.
EDIT: Also pointing out that you don't seem to waste materials by disassembling and rebuilding, so feel free to remodel the layout once in a while.