I often experience severe drops in frame rate for no apparent reason. Not sure if it's a problem with my internet connection, the game or my computer. Thought you might want to know about it.
You can shoot out of the water, but you can't shoot into it, that seems kind of unfair. I say you should either be able to shoot into water, or not be able to shoot out of it.
The bolts on the guns are too far forward. The bolt should be above the magazine, not on the barrel. You should probably fix that, or people will think you've never seen a gun before.
That happens some times, if it gets too bad, you can always save and load. That should fix it, or turn off the minimap by going to the options