That's why in my first post I said they were upgrades.

Apparently the reason why Capcom made the two upgrades was because they couldn't fit all the characters and stuff into one game, so they made Hunter 2, but for fear of it being called a complete rehash of Savior, they took the endings out and replaced them with one big Pyron-based ending, making it more of a "what-if" game based off the events that happened after Nightwarriors Revenge (which explains Donovan, Pyron, and Phobos/Huitzil's appearances).

And they changed all the music to that of Nightwarriors' Revenge as well (along with the color motif). IIRC, they also changed the Dark Force command to Dark Power.

Savior 2 I don't remember all that well, but the Pyron ending was changed into a Jedah-based ending. That upgrade was actually pretty pointless.