Great stuff :)

Thanks for your encouraging comments. This is my first contribution to a Pixel Joint challenge, and all advices are welcome.

Overall palette tones work well together, especially in the central part of the pic. 

Some places seem a bit raw though (for example the light green next to the dark greyish blue where the light hits the water), transitions could be smoothed with just a pixel of intermediary colour.
On the other hand, I think some colours (like the grey ones for the stalactites) are redundant: they increase your colour count without adding a lot of visual impact.

Love the falling water and the warm light on the god face statue, this kind of effects always look nice.