I've just replied to another listing on here but I'll reach out to you in an email as I'd like to inquire as to what you're in need of in terms of how much work and what kind of budget. I'm a huge fan of the retro inspired sprites and I think that we could probably make something work.
Here's a retro inspired mockup of a game concept, clearly inspired by Metroid:http://i.imgur.com/ISSGveh.png
Something from a while back (top-down arpg):
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It's not my best work, but should give a general idea of my capability as an artist. I have other more 16-bit related works and a heavily mario inspired creation that was created for fun as a hobby project as a parody but imgur is giving me errors right now (over capacity or something) hopefully you can view the above posted links, if not get in touch.