There isn't one, but the NES version is free if you want to try it out.
What is the difference between the GBC version and NES version?
the colours maybe?
The games share the same codebase so they play essentially identical. The big addition to the GB version is the addition of multiplayer. There's some other minor upgrades like battery save.
I bought it in Delta emulator on the iphone the NES version colours are more vibrant than the GBC version
