*BOOM BOOM BOO- Crashes computer*

Ah those where the days, being able to customize your super flat world

Can still do that though?

You can?

Yes, when you’re making a superflat world just hit the customize button.
Then once you do that there should be a text box at the top with some numbers and different block types.
The numbers adjust how many layers of each block, and the name decides which block is used in eavh layer

Oh lord if I do that I think my PC would be classified as a lethal weapon

I once did that to my superflat world and just blew it up, on my old small laptop that couldnt even handle 1.8