Add a new Retro Mode!

This mode, when creating a world, would give you a Minecraft world, but its dimensions are X=infinite, y= usual y levels, and z=1 block.  Yes, this would make a 2d Minecraft world.  This would add some unique challenges to speedruns and other challenges this would also effecter the nether world as well.  Biome structures are not effected by this to allow ruined portals to work, and end portals to be usable.  You wouldn't be able to build out of this range but the void and build height would be the same as usual but only 1 block of depth.  The end wouldn't be affected by this to allow the ender dragon fight to still be the same but if anyone has ideas on how that would work, please speak up!  Thanks!