I have not seent he movie. I like Poseidon's cape; but I do not like his helmet in the movie. It looks a little weird. He should wear a crown or a gold wreath on his head, my opinion. Excellent drawing here, though!
Are you sure you're not just jealous that Poseidon holds a higher water-title than RIVERKING? Ha ha, just joking man. A crown or wreath would look nice but I like that the helmet was kind of weird looking, I feel like the gods are too often depicted wearing the same old clothing.
Oh I'm not jealous of Poseidon. In my story, Poseidon [link] picks on the wrong ship and is slain [link] by a mortal sailer who becomes the new god of the seas. Haha But I should have had a crown or something to wear on my head for the pictures. oh well.
I had too look up the trailer on Youtube. The movie / acting was a bit like in a cheap sword-and-sandal production from the 50s, but like you wrote, the outfits were quite nice. For the headgear here, they seem to have taken inspiration from fashion editorials, where photographers strangely like to outfit their models with outlandish constructions.
I like your drawing though, the face is bold and manly, so he can pull off the strange gear on his head without looking ridiculous. It's also a tad more detailed than the rest of the picture, which works well and makes sure, it's in the focus of attention. The still quite detailed chest piece is the second rest for the eye, before it wanders further down to the belt, where the reduced detail kind of serves as a signal, to wander back upwards, a nice and successful composition.