FFish LOZ I'm in awe.
Let's step back from it being LoZ for just a moment and critique this work upon its aesthetic value.
First, I see no shortage of effort. There are minute details that I would guess must have been painful to exact (ex: hair/fur, small emblem designs, "the Legend of Zelda" title itself, as well as others).
The usage of figures not only achieves the viewer's satisfaction by gazing upon fond memories of the game, but it also accomplishes horizontal balance. If you hadn't have put anything behind Zelda's head (to the left), then Ganon's figure would have outweighed the right side of the picture. Had you put, say, another person there rather than the castle, it would have worked but, in my opinion, would have been slightly too repetitive; the castle is a great addition to slightly mix up what the viewer is looking at.
Your utilization of organic and geometric shapes/figures also brings about balance and harmony to the picture. So many subtle differences among the overt construction to help bring the picture together.
Another thing that makes this picture superb is how well you used shading, tints, and hues. It's always pleasing to the eye to look upon an object that logically makes sense, but to satisfy this on a two-dimensional surface can be a challenge, especially since this is fantasy related, not, for example, a still-life or portrait. Throughout, the blends of colors and shading/tinting is used heavy in certain spots and tasteful in others. Take Zelda and Ganon's cheeks. Without shallow use of shading when appropriate (and deep shading otherwise), the faces would not be accomplished and the facial expressions would not be full.
I get the impression that the light source of the background figures (Zelda, restored Midna, Ganon) comes from the left. You keep it consistent across all three figures, which is pleasing to the eye, as well. If we look at how those figures are arranged, it's very appropriate to see Zelda on the left near the light source, Ganon on the right where the light is least (and the background is deep blue), and restored Midna in the middle where the transition between both worlds occur. Well thought out.
In the foreground we see a separate scene. Link, Midna, and Link in wolf form. This is where a couple things leave me wondering. I believe I see Midna and wolf Link interacting and acknowledging each other (as they should), but I'm not sure if elf Link is supposed to be in that interaction relationship, as well. My best explanation of that would be that the Midna is between the two main forms of Link as their connection, interacting with both even though they aren't/can't interact with each other (for they are the same person!). If so, that is quite brilliant. The other thing that left me wondering is elf Link's facial expression. Is he confused? Perplexed? Lost? Honestly, none of those guesses would make much sense to me, but just because I don't understand it doesn't mean you didn't have a worthy purpose. Otherwise, I like what you did with elf Link. Quite often, he is depicted as looking slightly feminine, so this isn't far from home. He is an elf with soft elven features (which is consistent with Zelda's features). Personally, I like very much how you took the more elven approach to Link's construction. In the game, I thought he didn't look elvish enough!
I played OoT, MM, WW, and TP (along with some of the older versions). I'm familiar with the series and I have to say this is extremely well done. I'm sad other's don't give you as much credit as you deserve for the effort you put into this work and I hope you are proud of it, as well as the other works you've done. I was glad to see the Master Sword and the funky black/purple rectangles that float in the sky from the game. Those were nice touches.
Thank you for your devotion on this picture. I take off my hat to you.