There are two PlayStation versions: Version 1.0 and Version 1.1. This latter would become the base of every subsequent port.

1.1 version fixes a few things:

- When you encounter Nemesis at the park for the 5th time, there is a glitch where it could get stuck in a certain corner. This was fixed in 1.1 version.

- In 1.0 version the Music Box puzzle is randomized. In 1.1 version Music Box puzzle solution is always the same. This was presumably done for people who had hearing problems to figure out the puzzle solution, as the puzzle relies on audio memorization.

Source: https:/​/​tcrf.​net/​Resident_Evil_3:_Nemesis_(PlayStation)