Volvagia looks gorgeous...! And I love the colors. A thing that did stick out to me was Link's stance, though--it looks pretty nonchalant for a guy who's just had a dragon pop out of nowhere.... Still, this is awesome. The detail and textures!
Ah, this looks fantastic! I love how Volvagias eyes look rather challenging than evil. His hair also looks very good!
Though I've never played the game, I really love this character, because I've read the manga, and I really liked how the illustrator portrayed him as an old friend of Link that got possessed by evil. It really hurt Link emotionally to kill him. I think you expressed that sentiment very well, that Volvagia isn't just another evil boss but something Link recognizes from past times, and also his hesitation to act can be seen clearly.
I made it through the game so so so much faster when I did it again a few years ago. I had this idea in my head that it was this crazy hard and difficult game and I would be playing it for forever because it took me SO long as a kid to get through it. I flew through it lol. Except the water temple, that still took way to long. Was lost so many times
At a certain level of skill, it becomes very difficult, if not impossible, to offer advice that will help someone improve in raw ability. I can give you a couple of pointers, though, depending on what program you use.
My first guess is Sai, and I'm not sure if that program supports custom brushes, but I think the most valuable thing I can tell you is that you should work on texturing. For something like Volvagia, this would really benefit from some scaly textures. Some of your edges could be a little rougher as well, like on the rocks.
Your color range is pretty good and the lighting is nice and dynamic. I know it sucks, but it's hard to be a good art critic and very, very few people are willing to tell you anything useful unless your problem is glaring. The best thing you can do for yourself is keep practicing, even when you don't think you're improving.