The game can be completed in 5 hours and your only alternatives for replay are to play in a split-screen mode or use the difficulty setting.
The storyline for this game is set two years before the movie itself, where you participate in a mission for the cause of humanity. The game follows John Connor from his beginnings as a lowly soldier, all the way to his ascendance as the leader of the human race.
Despite the novel movement system in Terminator Salvation, the action is unfortunately not as much fun as it could be. There is a movement menu that pops up when you are in cover that allows you to use the analog stick to travel to the next cover position. While this is a nice, unique system, it is not consistent, and sometimes leaves you vulnerable to fire, or forces you into a jam. Your AI allies are there to lend a hand, but they too are inconsistent and don't prefer to attack with their heavy weapons.
That means it's on your head to pick up the heavy weapons, like rocket and grenade launchers, when you come across them. You can be sure that enemies such as the giant Hunter-Killers will come after you, so you'd better have the firepower to be able to handle them. Other than those, however, there are only three different enemies to fight in the whole game. Each one has a specific weakness to a weapon type, which makes combat a simple formula of match up your weapon to the enemy you're facing. After the hundredth time of taking cover from an enemy, blasting at them with the right weapon type, and flanking them if you need to, you'll probably be bored by it too. The enemies don't have a lot of tactics to fight against you, and usually just shoot at whatever cover you're hiding behind before they die.
It might seem like five hours of waltzing through post apocalyptic LA shooting robots would sound like fun. It is, however, only five hours of content, and yet a gamer pays full price. A second run-through on a harder difficulty is about the only option available to a person who has bought the full game. This might be fun for a little while, but is definitely not one to buy. Rent this title if you want to pick it up.