Flashback was such an amazing game. I spent wayyy to many hours on it as a child. I sadly only ever played the sega cd version, but it was quite a good port IMHO.
One interesting tidbit from that version. The manual that came with the game had a screenshot that had a password to a random level towards the end of the game. As a kid discovering that in the manual was an amazing feeling, especially when you weren't able to get past the 4th level or so.