The deal breaker for me would be the jump mechanic/physics. Get that right and I'll be there. As much as applaud homebrew devs, of the (admittedly small) sample of homebrew platformers I've played, none seem to have got the jumping right. And I think it's such an important area. Jumping in, say, a Mario game, feels so much better than in many other platformers, and I think it's one of the major reasons why Mario games have stood the test of time. Kid Icarus had a very distinct jump mechanic as far as I can remember. I imagine trying to effectively reverse engineer that would be a major challenge I would think.
But good luck anyway. I downloaded Kid Icarus on the VC when it came out on that with the intention of playing through it again. But I never got around to it like so many other retro games I've been stung with on PSN/XBLA/VC, maybe the Pandora will be what is required for me to bother picking it up again (after all, it looks arse on a HDTV but will look sweet on the Pandora). I hope your project turns out well so I can play that as well.