Great graphics, terrible story, uninteresting and unoriginal gameplay, gimmicky multiplayer
The multiplayer gameplay is a mixed bag. I didn't find it to be better than COD or Battlefield, and some aspects were very frustrating to deal with. For example, it's very common for players to use Proximity Mines, which are basically motion detecting sticky grenades that explode when someone comes near. If someone sticks 2 or 3 on the opposite side of a doorway you're about to walk through, you'll almost always die. Perhaps patient players carefully walk through the doorway then immediately take a step back so they can fake out the mines. But this isn't a very fun action to do over and over.. and over..
Another annoying aspect of the game is how the Infiltrator class behaves. This class can disguise itself as a member of the enemy team. If the class shoots an enemy, or gets shot, the disguise falls off. There are various ways to counter this class, but it seems like it takes far more effort to counter the class than to use it, and the counters are tedious to perform. An enemy team full of Infiltrators ruins the game.
In games like Team Fortress, a disguise class is very limited in its killing ability except in very ideal conditions. In TF, the spy needs to backstab an enemy. Outside of that, the spy will usually lose a 1-on-1 fight. In KZ3, however, the Infiltrator has basically the same weapons as the other classes. In a 1 on 1 fight, an Infiltrator charging head on against an enemy has fairly high chances of winning.
I also had issues with the game's net code. Perhaps this is just a problem for my connection, but it seemed like the game was 1 second behind everything that was happening. I could shoot someone "dead" but they wouldn't actually die until a second later. I guess it's possible I was playing on European or Japanese servers though. There is no server browser or indicator of ping/latency data so I have no idea how bad my lag is, or where I'm playing.