I've stated several times it was an inspiration, and I'm going to include that officially in the art book PDF. It's never been a secret or something I've tried to deny! I'm sorry Kana is a princess at times but you'll get to know her more thru the game! I'm glad you enjoyed Haruka's ummm... special brand of spelling and grammar. :P Thanks again!
Ok, I think you should make the inspiration behind it more clear, because I can't find any mentions of DDLC. And you should probably also put it on the game page. Idk... it just seems a lot like DDLC in some ways. I didn't like it especially when people thought you came up with the idea of looking in the game files, and the creepy glitched out parts.
On the other hand, the mystery person (btw I went in the files and saw the bowl of something (I forgot what it was) with a face in it which was hilarious XD) is a different approach in things from DDLC. It's the way you did the glitching and the game files that make me notice the similarities.
I've mentioned it on Twitter, on Discord and on my YouTube regarding the game. I've also mentioned it in comments previously to others, so it's never been a hidden aspect. I understand that you find the lack of mention disheartening, it was never malicious. The link (I thought) was apparent, even without me confirming it. I was hesitant to add the mention of 'Doki Doki Literature Club' into the game itself, as that isn't my game and it's not my property to be mentioning.