You make some very interesting points. I'm VERY glad you see it as an Undertale parody, instead of a knockoff or a clone or something lol. Means I'm doing something right :)
This is going to get a little spoilery, but hopefully it peaks your interest:
I'm planning for the rest of the game (after the next release) to shift away from teasing Undertale, and focusing on new concepts GE has to offer. I'm using the lack of subtlety, parodies, and references early on to set up a point I'm trying to make... One that will hopefully be clear in the next release.
The only fourth wall breaking that will definitely need to persist is the game's acknowledgement of the human player. This isn't just to be "creepy" or "meta" for the sake of it; It's to develop a very special mechanic later on that the player has hopefully never experienced in a video game before. This mechanic will establish context for many ideas that you see now, and ideas that you'll see later.