Ahh I've known about this, it also applies to RE1, and you could say 4 to a lesser extent...not sure about 3 though.
RE2 has the craziest amount though, I almost want to buy some extra copies like the N64 copy for that alone at least. A store near me has it...a lot of these I didn't know, from the subtle ones like the guy who says "Resident Evil 2" at the start. Dreamcast was also interesting, hmm.