Thats because you are doing the same thing over and over, I haven't played the the new Manhunt but I'd imagine the formula and mechanics are identical to the original.
Sneak, sneak, sneak, stalk, stalk, KILL.
That was all I remember doing in it so its no surprise that this game will get average to poor raview ratings.
It was obvious from the original Manhunt game, the 'Ultra' violence was the gimic and now its the previously banned label that will sell it to the masses, yes the very same mass of people that suckle at the teet of monotny... I'm off to play Fifa now, lol, only joking