-Loadouts are back ( :/ ), but they're tied to a "currency" system based on performance, so not too bad.
-There's an in-game leveling system: everyone starts at 1, and performing better levels you up, allowing you to buy better items with energy, that looks like it fills over time

-Along with the enemy AI, there are also Red and Blue marines
-The AI fights, and interact with you (capping bases, and they even sometimes wave at you)
-There are bosses, in the form of Elite generals, mini-Didact guys, Banshee bullet sponges, etc...
-Capture bases, like in Battlefield's Conquest mode
-There's requisition stations, where you can purchase guns and vehicles while alive
-Forerunner turret, called the Splinter Turret: kinda like a missile pod, without lock-on
-The Mantis can do little evade-jumps