They added 9 more music discs, they get progressively weirder. The 10th one starts out with a Death Tune. The last, 11th disc looks broken and ugly... AND HOLY forget IT'S SCARY.
Everyone knows how Hardcore mode looked like it'd be on the extra options screen for making a world? He moved it to be a third option along with Creative and Survival, but right now he forgot to remove "World is deleted upon death." from the extra options screen. Looks kind of stupid, and startling at first.