I think it would help in the later levels to feel more Contra-like, the ones that are more industrial like (in line with what fans saw in the PSOne/PS2 though looking at some videos of those, I am hard pressed to see any "iconic" characters to pull. Though, honestly, I grew up with the NES Contra games so those are easier for me to connect with, I am sure fans that grew up with PSOne/PS2 Contras feel the same about those.

Also, I am a writer because I cannot do cool things like this. I do respect those that have the skill and knowledge to do it and don't mean to knock those that do create these awesome mods. Nothing but respect for them and a hearty thank you for doing it in the first place.