Your lair in Evil Genius 2 is bigger than you think: you can build over multiple floors. But how do you do it, and how do you add stairs?
While you can view every level of your lair by clicking the floor buttons on your bottom menu in Evil Genius 2, you can’t build on them right off the bat. Until you’ve done enough research, you’re stuck to building on one level.
You’ll need to unlock stairs by researching them. Head into the research panel, and click on the ‘Lair’ tab. In there, you’ll see ‘stairs’. It’s in the second column, at the bottom. Once you’ve unlocked that, you’ll have the ability to build stairs.
Once you’ve built a set of stairs in Evil Genius 2, your minions can then access the next floor, which allows them to build. Have fun expanding your lair onto new levels!
Bear in mind, though, that subsequent floors typically have less available space; a lot of the dirt is darker, and minions can’t break through this as easily. Again, you’ll need to do more research to unlock the ability. On the ‘Lair’ research menu, you’ll need to unlock ‘Advanced Mining Techniques’ on the third column.