Acting like something never happened ... now that i something NiCALIS IS good at... 
How about doing something in the first place, eh?
All I will say is I look forward to downloading this game. There is only one reason for this, and that is the fact that I belong to nifflas support forum. Night Game has been in the works for a little over a year, maybe more. There is really no possibility that this is not copied, and, affiliation aside, I don't think you realize that you aren't stealing some guys game, you're stealing freeware from Nintendo.
I don't think you were very careful when scanning for legalities, because if you were you would notice that Nintendo Freeware is protected by nintendo. Therefore, I am looking foreward to the legal result.
That had me puzzled slightly. Night Game/Sky became freeware at some point?
I think/hope you meant
Wiiware.
Although, could this possibly be helpful for Night Sky?
I mean, people play the free version of this and are like, "Man this was cool. It was a lot like that Night Sky game... I think I'll go buy it".
But will the people who've played Trundle be overjoyed or annoyed that
NG/S doesn't play anything like their loved Trundle did?
From what I can tell of Trundle, looks like the dev(s?) checked the first screenshots, got into work, tried to make the game look and behave like they thought
NG/S would. But without seeing the game in motion, was no verifiable way to tell how
NG/S would control.
And as far as I can tell, when Nifflas dropped the screenshots in the early days, he did quite nicely ask people not to make KS levels with NG-esque tilesets before the game was released. I think a level may've been removed and had changes made to it to remove those parts too. I can't see how this'd be any different.
In a nutshell, people can easily tell the "coincidental" similarity between the game styles, believe they're related. As JC Grim mentioned, it might help
NG/S by.. well, what he said. BUT. It'll give people expectations of Niff's game and those expectations will be unvariably
false.
But, doing something about it should be left for Nicalis, who owns the game. Nothing us folks can do about it. Anyone else making threats at 'em (apart from official Nicalis personnel) wouldn't really be helping the cause.