If you like your zombie-killing with a slice of finesse, then Dying Light could be the game for you. Techland’s first-person zombie slayer uses free running to traverse the open world environment, to get the jump on your prey or get away quickly if you’re being chased.
The game also uses a day and night cycle; scavenge during the day for supplies while you can, but beware at night as the zombies become stronger and you're likely to end up running for your life.
In the new E3 trailer below it shows off much of the free running, as well as plenty of zombie killing. Oh, and there’s that grappling hook too; check it out! *Warning graphic gore content*