Unlockable Special Awards...
If 2 enemies happen to be lined up, then it's possible to fire a bullet with a sniper rifle which will kill the first enemy, then travel through and possibly kill the next.
There are lots of glitches in the Port in Multiplayer. Many people have seen others hiding in boxes. This is just one example of the glitches.
1) Go to the Submarine Pen. If you entered through the hole in the red tank, turn right and go up the stairs. Stand in the corner and walk towards the corner of the railing that leads down. You should be floating in the air. Continue walking until you are above the box, and release
2) This one is more simple than the last one. In either of the stairs in the sub pen, you can walk up the stairs just outside of the railing if you follow the same technique.
3) Go to the bottom of the path leading to the sniper tower, and go onto the boat. If you run (c button) towards one of the obstacles from the middle of the boat, you can get on top of it, and even inside it.