Also, what is this "Corporate ERA expansion" that's mentioned on the back of the box? I haven't heard anything about this until now.
The corporate era expansion is included in every box. Calling them an "expansion" is a stretch, more like a module?
It is an additional set of cards that can be used to add more cards to the game. Most (All?) of these cards add additional engine building to the game, as opposed to focusing on the 3 end game parameters of Oxygen, Temperature and Oceans. It also does increase the length of the game when using them in a multiplayer game.
It should also be noted that whether you use beginner corporations or one of the 12 advanced corporations, you can still choose to use the corporate era expansion cards, or not use them.
They are also used in solo play.