Either rent it, or just don't play it at all. Whatever you do, don't buy this game.
The story is forgettable, as are the characters. You play John Connor. A man on a mission to take down the bad guys (or machines) known as Skynet. Throughout the campaign, there's never any sense of excitement. The voice acting is abysmal, and creates no urgency or fear in what are supposed to be 'intense' moments. Basically, it's a dull, forgettable story that fails to captivate your interest throughout the 4 to maybe 5 hours you'll spend playing this game in order to beat it. Once you do beat it, you can either play it on a harder difficulty setting, or maybe if you have a friend, you can play the campaign together via split screen. There is no online multiplayer, either co-op or competitive, so playing with or against anyone online isn't an option. Also, it's actually possible to play and beat the game only once, and acquire all the trophies. Simply play on the Hard difficulty setting, complete each of the game's 9 levels, and you will have probably the easiest Platinum trophy you will ever earn.
Visuals are far from next-gen standards. Cutscenes are blurry, character models are as well, and the environments, while somewhat detailed, are still bland.
Aiming is almost impossible in Terminator Salvation. You can try adjusting the sensitivity, but no matter what, it still remains difficult just to simply aim at your foes. Barely move the right stick, and off your crosshair goes to the left or right of what you want to shoot. Once you do manage to get an enemy in your sights, you'll find that the weapons you shoot have no real sense of impact, and don't even feel powerful at all.
Background music, and sound effects fail to portray what is supposed to be a chaotic battle against Skynet. At a few points in the game, you may begin to laugh at the music playing whilst you're battling the machines, as it sounds nothing like something that should belong in the game. Weapons sound equally as bad, as do the sounds of explosions.
Mediocre game play, dull, linear levels, broken controls, and an assortment of other various flaws make Terminator Salvation a game that's simply not worth its $60 price tag. If you really want to play this game, do yourself a favor and just rent it. It can be beaten in around 4 to 5 hours, and a game like that doesn't need to be purchased at full price. Overall, Terminator Salvation is a playable game, but it's not worth buying. It's a rip-off, so do the right thing, and rent it, or do an even better thing and just pass on it all together.