Endgame options have grossly improved. Overall, combat has been automated at endgame (artillery trains automatically destroy, and automatically explore the map for you). Nuclear bombs can be used to one-shot endgame biter bases.

"Alien Tech" has been removed. All technology options are built traditionally, and now have 7-tiers with names. Red, Green, Grey, blue, Purple, Yellow, and White (aka: Space/Infinite research).

Infinite research are ~7 or so techs at endgame which go on infinitely. +Weapon damage for the most part, but there is also +Productivity (which makes mines last longer and mine faster).

In effect, the core gameplay loop has been extended into an infinite endgame loop. The late game techs are extremely powerful and automate everything that was boring ~5 years ago (ie: killing biters became boring. So its now fully automated with artillery trains).