I beat the game a day or two ago. Fun game, like Que I'm kind of surprised it didn't do better (at least after the price dropped).
One thing I didn't like was the use of climbing over things and grabbing things. Like, they never felt consistent with me. Maybe it was my control configuration. I had middle mouse button for reload/use and End for sprint/mantle. Some things required one, some the other and I always hit the wrong button first.
Some of that mantling stuff was annoying too. Crawl through a vent and its like 3 feet to the floor and in any other game you just come out and drop. But no, they wanted to do a fancy first person animation so you have to "use" the edge of the vent to crawl out. I thought that was dumb as hell. And the left-right-left thing when crawling across stuff was also kinda lame. You earned points for the timing but I kick some fucker into a cactus and there, I've made twice as many points. Just didnt add anything to the game.
But thats just me picking nits. Leash some guy towards you, sticking a bomb to his head, then kicking him back to his friends for detonation was great fun.