So this game that has the record for most crowdfunded, now at 128 million USD from pure crowdfunding... has gotten to a milestone much earlier than anyone anticipated. They've gotten to a biome-based procedural planet tech, which is also editable.
They've gotten very far in their heavily modified CryEngine, now unofficially dubbed "StarEngine." Many of the original Crytek developers joined the Star Citizen team back in 2013-2014. They have spent a long time to create the base tech, for example converting the positional space of the engine to 64 bit vector math. And a lot of other stuff... but it's finally paying off.
Semi-scripted (but real time) demo of a scenario
Showing off the planet-editing tools (probably more relevant to Terragen community

)