Buy Psi-Ops RIGHT NOW.
I have never had such fun in a game. The physics are incredible for a 6th gen game and tossing enemies around with abandon is so fun. It isn't like Half-Life's gravity gun, either. It gives you full control to pick up and manipulate objects, allowing you move them slowly and peacefully into another place or toss them violently and it allows you to pick up almost every common enemy. The story is quite poor but you CAN MAKE PEOPLE'S HEADS BURST WITH YOUR MIND, WHAT MORE DO YOU WANT.
Destroy All Humans gives you a similar level of power, and it takes place in a series of highly destructible sandboxes. By the end of the game, you are powerful enough to lift and throw giant mechs. Also you get a flying saucer! It's another 6th gen multi-format game and it is incredible fun. The sequel is good, too, but less so. Never played the 7th gen entry. The writing can be pretty funny in this one.
Second Sight is more of a stealth game but still gives you that level of control and the ability to pick up and manipulate enemies. Your other psychic abilities make the stealth very creative and fun and the narrative, whilst nothing groundbreaking, is interesting while you play.
But yeah, these games all give you much more flexibility and control than your Half-Lifes and whatnot. Well worth playing, all three of them.