If the game crashes all progress will be lost since the last time you "Quit to Title"

For example:

1) Dig a tunnel
2) Duplicate the Furnace Crash issue
3) Tunnel will be gone, but the stone you collected will still be in your inventory.

It looks like your inventory is constantly saved and updated, but the world status is only saved when you "Quit to title"

This crash is incredibly annoying if it crashes while you are in the tunnel. You will respawn embedded in stone, because the tunnel does not exist anymore. The next respawn might have you respawn on the surface or permanently embedded in lava. If you respawn in lava there is no way to recover the game.