My theory is that there is a special effects layer. This layer contains the ambient lighting effcts and the water effect. The said layer can go over all other layers like a layer 0. However do to that fact of cheapness they can only store ambient lighting or water waviness. Not both. And seeing as you can't get water to turn off, when you hit a water event your lighting goes away. The only reason of this problem is laziness and rushed games. If they had the time they could have made a 2nd sfx layer and/or a water turn off valve, but we got the best we could do.

though think about it: do you want to swim in pitch-black?

Thought not.

Your theory does not explain why they worked together in OEM. Ambient Lighting simply only applies to underwater if there's water in the level, that's all. (Look at Beach2... you can see the water change colors every time you pass through Set Light areas)


Xion: Lagunicus.

In the OEM there was no foreground waviness.

In the OEM there was foreground waviness, but the water did not change the lightness/color of things behind it.

Good theory, but I think it's more of a "lighting layer". The water without lighting modification works fine with lights.