Contra S.S. & Neo Contra: US vs JP?

[BIL]

Thinking of picking up both of these games again - just wondering, does anyone know of differences between the US and Japanese versions (particularly where difficulty is concerned)? I've played the US versions of both to death - if either was a bit tougher or just notably different in JP, I'd love to know.

[kid aphex]

Anecdotal:
I played both versions of SS to death, and never noticed any difference in difficulty
No experience with Neo though

[BIL]

Thanks - I couldn't see any difference in an NTSCJ S-rank on Youtube compared to my US runs (besides "Hit Rate" being in Japanese text), but I've never tried firsthand.

I don't think Neo could be much easier than it already is in US, to be honest. Part of me hopes it was watered down for the West, but I don't think I've heard of any Konami game being more difficult in Japan.