Timeshift is actually fun if you give it a try.
Sound: 6/10. The sound isn't all that great. The guns are good. But I could barely hear the voices. It's like you have to set the music and sound effects to 20, and voices to 100. They could have done better,
Gameplay: 8/10. It's pretty fun. You can control time. It would have been a bit better if you had a longer time meter. Also some of the parts were REALLY tenacious. I mean have to do them time after time after time. Because you didn't know which power to use, or you just kept dying. But the "puzzles" I could figure out most of the time. Even if it took me 20 times. The only part I actually needed to look at a guide was the last "boss" battle.
Story: 2/10 Let's face it. There is no story, and if there is, it's hard to find. Even with what they give you, it's pretty confusing, if you're looking for a good story, this is the absolute wrong place to look for it. All they do is show 5-10 second cutscences. You never know what's going on. You just know what's vaguely happening.
Fun factor: 8.5/10. Even though several parts are hard, and confusing, it's still fun. I mean, you can stop or slow down time. It's always fun stopping time, grabbing you're enemies weapon, and watch them be defenseless, then shoot them with the scatter gun.
I wouldn't buy this game, but it's a good rent. Good fun. While it does have it's bad moments, I think Gamespot was a bit too harsh on it.