I guess everybody knows what is a CD or a floppy disk even if its retro and in museums right now (look the game: Unusual Findings who plays on this retro feel all along.)
The problem with the puzzles of Kathy Rain was there absurd difficulty and lack of interest for making progressing the history, if it makes the game potentially longer it can also totally kill the fun. Hacking a PC (many times), editing a picture, hacking a soundtrack with 80's software (with hardly no clue on what to do or why) Even for a purist from the 80's was hard and boring. And the worst in all that is that they seem to have put more of those exact same horrible passwords and hacking puzzles in Kathy Rain 2. IMHO, Wadget Eye games is the only guy that can create smart and not boring password puzzles (and with parsimony...)

I'm trying to think what sort of software I would use for the voice thing? Audacity seems the likely one. Gimp for the photo. I doubt something that old scanned into the computer would render such a good result though.