Yes, all floors would be the same, but all the monsters would respawn once you descend to another floor or die. I think your idea of practical effects would work. Here, I did a quick little pixel sketch of how the first floor and such would look like, also a little way of describing the rooms.

[hider=Map][img=http://i.imgur.com/4qFwsbS.png?1?2796][/hider]

I'm typing up a little bit of a descriptive map of the place, which is why I had the numbers. I started on it about 5 minutes ago. The first number is the floors, second number is the room.

[hider=Description][list][*]Infinite Spirals[/*]
[*](1,1: Spawn room, only characters. No equipment. Exit south.)[/*]
[*](1,1.5: 3 slimes. Treasure chest. Exit south. turn West or East. Slimes: Harmless. Drops basic weapons.)[/*]
[*](1,2:[/*][/list][/hider]