A video game. Terminator crossed with Helldivers, set on a big open battlefield in the future.
The resistance is controlled by the players, AI controls the machines. Players can conquer time machines to go back in time. There they clear small side missions to change the battlefield in the future.
Okay wait a second this is pretty huge.
Take your idea, incorporate a StarCraft element in terms of enemy numbers. Succeeding in a back in time event wipes put a portion of current time enemies, but failing on adds more of them or wipes out part of your team (maybe the members from back in time don’t come back for the rest of the round)
Yea. that is pretty much what I had in mind. A huge persistent battlefield with an ever changing frontline. Players who fail the time travel missions lose their character, but succeeding sents equipment or units to the future or hinders Skynet in some way.