Main feature is that Corrundum is now too inhospitable to land on, you have to conquer the planet remotely. You can use orbital vehicle deployment to start.
No major tech tree changes, only a few additions to make it easier and to contain somewhat relevant mods. Most of the additions are unlocked from the start.
Now there are also abandoned mechanical bases spawning here as the only things that can survive. (they are closer to vulcanus worms than anything else, you can go around them if you can't take them yet)