Some things I've seen while binging people's Deltarune theories.
A lot of theories are kind of like Deltarune is taking from Undertale. When that's... Probably not true. Deltarune is a project Toby was planning before Undertale. But it was too big a project to be a starter. So really the statement should be, what of Undertale was taken from the concept of Deltarune.
We can safely assume that most of Deltarune's story was planned out if not complete. How would Toby have known it was too big a project otherwise. We can also safely assume that Toby was really set on this story! He made a different game instead of just making Deltarune a smaller project.
So with that we have a concrete idea that Undertale takes from Deltarune, not the other way around. And now you can look at characters a little differently. Toriel, Asgore, and even Temmie.
Toriel and Asgore's relationship is pretty fleshed out in Undertale. They were together, Asgore became depressed and made some tragic choices, Toriel noped on out of there and said bye. It's actually pretty simple. They aren't super fleshed out beyond the needed backstory to give them their roles. But in Deltarune, they become their own people. Asgore is a man on the ropes, he has friends, but he's a desperate man trying to get his family back. We're not even sure what he did, but it's enough for Toriel to want nothing to do with him, still care for him in some instance, (shes worried about Carol enabling his hobbies that might be trying to prove himself innocent or finding Dess), and not talk bad about him. (In Undertale she's openly pissed off about him, in Deltarune she's very amicable if awkward about him being brought up so far.) And Toriel is a... Not great goat mom. In my opinion she was always not great for the humans in her care. She lied, tried to keep them locked away. And then even knowing they would die, refused to go with them on this perilous journey through the underground. She was just like, "dont come back traitor" and then depressed when they died come on!
And the mechanics are simplified as well. In Undertale we play as a human that we are controlling. But there is no nuance of does this character want to do what Im telling them to do. Is the soul and body on the same page. The concept of a soul controlling a human host isn't new, we just got more details. Toby simplified it for Undertale because that was his first game! Cut out the things that make making a game harder.
And lastly. For this all to work with Gaster and what not? Deltarune had to be a forethought. Whats the point of adding a character to haunt the narrative, if in the end they mean nothing to the story. Alphys becoming the Royal scientist would have worked just as well if her predecessor simply passed away. And wasn't some guy who got torn to shreds by the space time continuum. Gaster being in Undertale was Toby's way of saying there is more. That there is more he wants to share with us. And that more was Deltarune. What better way to introduce this crazy experiment guy outside the game you're playing, than with a game that leaves hints about how he ended up where he is. Hints, I remind you, that lead to ZERO actual answers.
Anyway I've made my point. We have to stop thinking of Deltarune as a copy or taking likeness from Undertale and start doing the opposite. I understand we have all of Undertale and not all of Deltarune, but that doesn't change the order in which they were thought of.










