When I first discovered ace of spades, I went in the water so see how it was like, straight away I noticed that you could not go under the water, only on it. I was frustrated by this, no going under the water so hide from enemies, and not being able to be tactical and stealthy.
You can easily see on the map where the deep parts are and where the shallow parts are, and yes, the ground level under water will not be flat. The sea floor will not be breakable but you will be able to build on it.
The visibility in the water will be very faint (an enemy on the surface, looking in the water at another enemy), compare to on the surface, maybe be a blur or faint colours.
I'm stumbling across whether you need air every no and then or to have unlimited air under water. bullet damage will not be affected in the water.
I know this will be hard to make, but this would be good in the next update
CONTROLS:
Space bar = swim up
Ctrl = swim down
Hold space bar to stay on the surface of the water
W = forward
D = right
S = backwards
A = left
if you release space bar you will slowly sink
paragraph 3 maybe hard to understand:
person A is under water, person B is on the surface, in person B's view, the visibility of person A