Something I like is when I can immediately distinguish between two artists. This is one of those occasions, both Kirby and Nina have fairly distinctive art styles. In this instance I'm led to decide between a very clean pixel style, and a more extravagant one. This makes it somewhat difficult to actually choose between the two.
Kirby's work here is a fairly advanced piece of pixel art in some aspects. The first thing that jumps out at me is the fact that there is some subtle blue mist around the sword which is actually quite difficult to do in itself. With some really well placed dithering this went from a risky lavish addition to a really fitting elegant effect. The design of the sword itself seems somewhat impractical from this perspective. Below the hilt it's hard to understand why the frilly "grate" would be there. I foresee that being quite hard to hold and imagine it getting in the way. Of course it doesn't have much bearing on the piece itself, but it's a design choice I found to be quite odd. The sword itself is a bit odd once you begin to break it down piece by piece, and personally I don't hold much love for the overall blacksmithmanship; that isn't to say the sword isn't well sprited however. I'm just not as big a fan of the saber as I am of the shield. The shield itself is a much nicer design, again a bit on the impractical side but given that Kirby has gone for a more fantastical style I'll forgive it for the sheer awesomeness of the creation. The blue and orange colour combination is very common in things like
movie posters, but I'm not really feeling it here for some reason. It's a minor gripe in an otherwise strong piece of pixel art for both the sword and shield.
As for Nina's, I'm less blown away due to the style being a lot more safe. Which isn't necessarily a critique here, because Nina pulls off a simple style with well drawn assets. The sword in particular is something I enjoy, it actually looks like something you could swing yourself. Proportionally it's more feasible than that of Kirby's; even from a fantasy perspective. The shield looks as if it would have been quite tough to make, giving it a shine like that is something I know I would personally struggle with. To me, it works in most instances but I can't help but feel there's something off about the shape. Slightly wider might have worked nicely, but the shield's real qualities are in its inlay; the intricate designs drawn in and the way in which it is allowed to shine. The colour palette and style feels very warrior Zelda, but works really well in that sense.
I feel a bit bad voting the way I'm going to here. Both parties created great pieces but one went above and beyond in terms of pixel complexity. Nina's works are very good, very clean and would suit a particular style of game, for example. However Kirby's works really stand out and if I were to create either of the sets myself hers would take the longest and most attention to detail.
It is for those reasons I'm opting for Kirby on this one, it really boiled down to sprite complexity as opposed to lack of technique used by either artist. So kudos guys, and best of luck with the battle!