Wait, is Shine Mirage really a sequel, or you are just assuming? I haven't played it yet, hoping for -probably in vain- a similar official English complete version, like it was with Mistletear; but never realized/knew it was a sequel.
I 100%-ed this one, it was sooo long ago though that I barely remember, but can't seem to recall having problems with that particular achievement. You should check and search the ULMF thread (after searching this thread, if you haven't, yet) for info.