I just finished Deltarune Chapter 1 and I have a lot of feelings about it. I will say that Undertale hit me more emotionally and told a better story, but that’s also me trying to compare a single chapter of one game to the entirety of another.
Playing it blind was an absolute treat and it felt great to delve back into another Toby Fox adventure. If you haven’t played it, I 100% recommend it. You can technically play it without having played Undertale, but you’re doing yourself a great disservice if you don’t complete Undertale first. They take place in alternate universes, but you will miss a LOT if you don’t have the context for the references.
I’m impressed that after a game like Undertale, Toby Fox still surprised me with this game and all it changes from the Undertale format while retaining the charm of its predecessor. It will probably be a long wait for the chapter, but I’m already excited to see how the story continues.