>>721078474
You're trying to invoke meta level establishment of subversion as an example but within the games its all incredibly consistent. You aren't lied about, mislead or faked out and Undertale very much establishes its rules and messages fine and dandy my guy, the whole point is that you're very clearly told the rules and expectations of the game within the game, its one not playing by usual rules but it is narratively coherent.
Within themselves, there is no real subversion. You're correct in that it means it goes against undermines or contradicts an established element, but there is none of that happening about dark worlds, there is nothing breaking their rules or even breaking character. If you make it where knowing more about a character you didn't know about is reader subversion because you couldn't guess it completely or an event happens you didn't see coming perfectly, I hate to fucking tell you but you're dead ass wrong, that's basic character development and event based storytelling my dude. You're trying to nail everything with the subversion hammer when this is just how things work on a basic narrative level across all stories depicted by media in general.
Undertale and Deltarune are internally consistent. They present the premise very clearly, explicitly and stick to their rules very very hard. They haven't broken anything, not yet.