Last Ninja Remix on the Amiga is based on the Last Ninja 1 ...
Last Ninja Remix on the C64 is basically the same game as Last Ninja 2 on the C64 (with different musics - thats why "remix" and a bit redesigned status screen - the game is the same otherwise).
So if you bought LNR on the C64 you were ripped off (unless you really wanted the new tunes) but on the Amiga you got the best LN game for the platform!