I don't know when I'll get to it, but somebody totally needs to see if the new fields used on asteroid spawning can be hacked onto other planet types. Infinite collisions? Perhaps ping-pong where you have to jump between colliding pairs. Metal-rich planets that appear and then collide as players flee back to their barren homeworld, awaiting the next cycle. Annihilasers and gas giants that show up late game instead of getting rushed.