I'm really apprehensive about this. Even if Konami was doing it, I'd be nervous. I just hope you guys don't over do the narrative. Contra is about shooting aliens and dodging all the crap that's flying at you from all directions. That's all there is to it, really. It doesn't need the "drama" and stuff from the PS2 games.
Also, Contra's supposed to be a little tough, but I thought they over did it in Contra 3. It's a problem when it gets to be unfair, like when it's just not possible for a moderately skilled and dedicated player to avoid every hit in the game, or when it just gets exhausting to try and do so like in Contra 3. Moments of intensity should be broken up by comparably relaxed stretches. I think that's what worked in the NES port of the original Contra. Many of the stages were really not that hard, but they had hard parts, and the bosses were somewhat demanding.
I know you guys posting here are probably involved in just the graphics, and I don't know if you have any say in design, but those are my concerns. I know you guys will have the visuals covered.