Thanks! I will change the switches and have a look at all the other stuff, too.
As you suggested the jellyfish now have an electricity glow around them when the player gets close, the area looks and feels much more vivid now!
Yes, the temple level is unfinished but I probably won't change the blue colored areas. It's a transparent glass with a few subtle light reflections over a sand background (maybe a little hard to see in the video, I think I will decrease the alpha value of the glass). The problem with the other glass effect is that it looks pretty bad on a larger surface, IMO there has to be "low structure" on those big surfaces or it will look a little disturbing.

As you've mentioned the target marker (on the "S" boxes or at 0:15+ in the video), does anyone have an idea how it could/ should look like? Because I don't...