LET'S GOOOO
Achieving water with the other turtles is ~1 in 100 trillion chance with RNG, if my math is correct (requires free digs on obsidian layer AND lucky restore cell placement with straight line digging starting from granite layer, esp. for Grampshell). Not going to bother until future updates, but for now, everything has been unlocked!
ETA: The sand and sticky mud layers are only 40 deep, whereas all the other non-lava layers are 50 deep. Is this intentional?