JuraxGames: You can press the M key to see the map screen. If you double tap it then it will stay on that screen until you press it again. When you're on the map screen you can use Q to go down stairs. You can also use your mouse wheel to zoom in or out.
You can play either mode like that but it's a bit easier to play the classic mode like that that since the rooms are simpler and there's no flying enemies.
I'm still tinkering with the controls for the map screen so if they feel a little awkward right now then I'm sorry about that.