Actually, I think you can swim like a plain. I never use the swim up/down commands.

I don't know how weapons handle underwater, or how military SCUBA diving works, but being able to swim into one and fire into another direction would be an awesome feature!

besides the underwater single mannned vehicle, everything is already inside the game

If you go diving in game you will notice that you can not maneuver freely. It is basically the same as if you where on land with the only difference that you can move in three axis and you are only able to fire while being still. So, all the features mentioned above are NOT on the game.

i think there was already a ticket like this, we ended up agreeing that its hard to dive AND shot at the same time, plus aiming.

I get what you mean but at least it would be possible to shoot straight ahead without using the ironsights.

wait, cant you? as far as i remember you can shot from the shoulder without iron sights even when standing still

i meanshooting straight ahead while swimming. i also discovert a bug. it is possible to shoot while swimming, but only with the "swimming up" and "swimming down" buttons. if you press the trigger in these two actions your character will shoot and the bullets will travel in the direction your weapon is pointing, which is to your left side to the bottom.

diving straight ahead and swimming would be making aiming easier, i am not sure if its possible though

anyway, what's important is the movement ability. It would add much more immersion to the diving experience if you would have to pay attention where the bottom and the surface are.