You start off in a battlefield. It looks quiet but all of a sudden a ship comes in, and robots too along with it no make that an army of robots trying to blast you to oblivion! Occasionally you'll find allies that are "fighting" along with you, but all they do is block your way, yell when you shoot them, and go "NOOOOO!". Next level, you find armies of Arnold Schwarzenegger? (It's pretty short.) Next level, you find yourself seeing a red truck driving, but robots are coming towards it and trying to destroy it! What do you do? You shoot some more.
You hear him say "move out" (once you've succeeded in protecting the truck. If you don't, you will lose a fraction of your health and will have to try again). It's John Connor!
Next level, you get through security (a lot of it) and pretty much destroy Skynet. You see something and you hear John saying "enter the time field generator!". You've entered present day! Next level, you, Sarah, and John (younger) are planting explosives and destroying everything inside (I believe) skynet. If you don't get the number required, you'll get a bad ending, but nothing else. Next level, you find yourself protecting a truck from being destroyed by a helicopter. When you succeed, you find a truck trying to destroy
it. Once you've succeed, you find yourself against the t-1000. A heath bar this is going to get ugly. What you have to do is attempt to freeze him by making the liquid nitrogen container leak out (by shooting it.) Once he's frozen, he melts and now he's trying to kill John! Just keep on blasting the annoying cop and if he gets too close, you can also use your shotgun. When you lead him into the edge, powerups should come swarming down all of a sudden.
When you see a rocket, shoot at that powerup and immediately use it against him. If you succeed, he will meet his death in hot lava. If you don't, you get another chance but be warned that he will be harder to stunned than before, so it's in your best interest to take him down as soon as possible. (If John gets killed, you will lose a fraction of your life.) After you viewed the t-1000 death, (depending on wether you destroyed the required number of things in Skynet), you will get either a bad or good ending. A bad ending would say that since Skynet wasn't fully destroyed, judgment day may still happen. If you get a good ending, obviously it's the opposite.