Ohhhh, but I DID!
You know, a few years ago, a guy made a thing called MooDDooM - taking the entire Doom game and reversing everything in it, even down to the sprites. And even though I've played the original maps probably a thousand times, it was THE single most damnably confusing gaming experience I've ever had. And now you want me to have the same experience in ZC?? No thanks 
I might actually upload this in my sig or something for anyone who wants a randomly mirrored Z1 OW for anything really. IIRC, you use to be able to flip screens, and maps in 2.10, but it got cut for being buggy, and weird.
I'd imagine the bugginess/weirdness would have to do with the fact that there would need to be a flip-combo index for most areas. Flipping a dungeon screen would invert the corners and angles of the bricks if there were no way to tell it, "hey, when flipped, swap combo 540 with 583 (or whatever) to retain angles and perspective."
But I could see that feature being useful for outdoor scenes with lots of trees and maybe some rocks.