Undertale is fairly well liked, but the games it's pulling from (like Moon RPG Remix) didn't exactly sell like hotcakes in Japan either.
DDLC certainly isn't hated in Japan, but at the same time it isn't put on a pedestal either. I'd look up the exact reception but I am at work and it turns out they have very nsfw banner ads on the main JP-language VN rating site (whoops). (edit: found a way around that, looks like it has a 76. A good score, nothing outstanding.)
Nonsense. "Testing" is for when you're still guessing--and now, I have no need to guess. -- Agatha, Girl Genius