Here's what happens, in my game, when Godzilla LEAPS into the water:
No splash effect. You can tell that the water is just a suspended texture. Why? Because the camera dipped below the water surface and, in fact, everything is the same color underwater as it is above. Also, when Godzilla hits the water, a bunch of pixels erupt as a sort of "fog" animation, but there are no water EFFECTS. This isn't Wind Waker. Also, when Godzilla is moving through the water, the only noticable effect is that pixels fly out behind him.
And when I say pixels, people, I mean it. They are WHITE, and they are UGLY.