This piece was done very well. The details in this make it look realistic as well as majestic. The detailed engravings on the Trident are simple yet beautiful. The only thing that irks me is the bottom part of the Trident which should be darker because of Poseidon.
The expression on Poseidon's face shows a kind of ancient
The reader is pulled in due to the intensity of the blue. But the soft background tones this down. On the top right of the picture, the clouds are realistic. However at the left corner, they take on a more foggy and mysterious quality. Was this done on purpose?. I really love how you've made the vein of the left arm prominent. And that the hair on this chest and the small marks are subtle but interesting details.
The amount of detail is this is amazing. This is great.