He’s still got a few left if anyone else is interested. Gameboy games are region free so it’ll run on any GB/GBC/GBA(except for Micro) that you have lying around.
The game is a similar deal to New Ghostbusters II on the NES only with different level design and without the 8-bit movie soundtrack. It has a few neat power ups though and you can also change ghostbuster on the fly (which you can’t do in NGB2).
actually any form of ghostbusters 2 that you find for the gameboy is this version of New Ghostbusters 2. Besides the differences you already mentioned you have to keep an eye on both Busters in your group as they both take damage unlike the NES version.
I actually just get a reproduction of the US prototype for New Ghostbusters 2, I had a PAL one but don’t like how the music and game runs a little faster on a US NES. Heck I never even knew there was a us prototype for it.