What counts as 100% completion in Wario Land 4?

[CM30]

Saw this on Reddit, so may as well ask folks here their opinions too.

Do you need to 100% complete the game on every difficulty level to truly finish it?

 

[Frigid Sea]

Unlocking Karaoke mode on S-Hard and leaving with all the treasure in Wario's hover car

 

[noobmurderer34]

I wouldn't count the easiest difficulty since the game only gives you 2 save files anyway and S-Hard I understand because of the hovercar, I suppose getting karaoke is a fun challenge too and I'd consider it completion, figuring out the intricacies of maximizing your score also happens to be one of my favorite things about the game (now that I think about it, are the score requirements different for S-Hard? I forget)

 

[CM30]

I wouldn't count the easiest difficulty since the game only gives you 2 save files anyway and S-Hard I understand because of the hovercar, I suppose getting karaoke is a fun challenge too and I'd consider it completion, figuring out the intricacies of maximizing your score also happens to be one of my favorite things about the game (now that I think about it, are the score requirements different for S-Hard? I forget)

I don't recall the score requirements being different based on the difficulty level. So coin wise, the later ones are probably easier in some sense.