"we've been coming here for years, but of course, its been redone"..huh?

I took it to mean that it used to be some kind of torture chamber type place, hence the decoration - so the joke was is they used to go when it was that and now its a re-done restuarant but theyve been going to the same place for years

No power in the verse can stop me

I always just assumed that it meant it used to look even worse. In other words, the cave atmosphere was supposed to be an upgrade from what it was before.