Okay, let me tell you a story.
I play my first minecraft level.
Everything is going fine.
I get a nether portal up, and then I start setting up another mine over a mountain to get more iron.
While I'm mining in an aboveground cave (I saw some coal and went to go get it) my PC freezes.
After several tries, I have to hit the restart button on my PC tower.
When I load Minecraft again, my save is gone.
I start a new level. I put 14 obsidian blocks in my inventory with invedit.
I get a flintstone and some iron, and start the portal up.
Strangely,
The nether is exactly the same. Blocks I had changed in my previous save were exactly the same. In fact, the exit portal was in EXACTLY THE SAME SPOT it was before.
Realizing my luck, I immediately enter the exit portal.
It lags heavily loading the world, and I find out I was correct.
Entering the exit portal of the nether reloaded my OLD save, and restored it.
tl;dr I figured out a minecraft glitch that lets you recover broken saves.
