It could also be showing you the future. Susie being mad at Kris working with the Knight, Undyne in the dark world being frozen by the knight in a berdly sort of situation, and Kris missing a hand. Although the other visions are Tenna smashed after you beat the Knight but before you exit the Dark world, Noelle whispering something to Kris while in Chapter 4's Light World segment at the beginning, in the first Sanctuary in Chapter 4 you see the Church's lobby, and whenever you use a crystal in front of the Prophecy nothing changes.
With the, The Man, our best Gaster candidate. Revealed to not be Gaster,
Other than that there's some interesting stuff looking back at Chapter 2. When Spamton was cut off from talking about how the Knight relates to communion, it was probably Kris threatening him to not spill the beans. Spamton also says that him and Kris don't need CRTs or easels, which is interesting as the man points Kris to draw on an Easel in the fourth Egg Room.
I bring up the Egg room since the room its connected two has some interesting dialogue from the leftmost bookshelf and the enemy there.
And so wept the fallen star, making rivers with its tear. Then, slowly, from the bitter water, something grew. It looked like glass.
Which seems to describe the creation of Shadow Crystals, which is interesting since we know that Darkness is for synonymy with Star in regards to the elements that make up Deltarune's world. Titans also have stars for faces, and the save points are white stars, meaning their creation may have something to do more with the Dark Worlds and Titans then Gaster. Although Seam seems to be trying to create the Pure Crystal that Malius can combine with the Thorn Ring(only accessible in the aborted snowgrave route) to create the Twisted Sword that lowers the trance stat of whoever is holding it. The Pure Crystal could also hypothetically be used to create the unused Sky Mantle item, which may be connected.
I do find the Twisted Sword being locked to the aborted Snowgrave route interesting, as you can't get the Chapter 2 Egg in the Snowgrave route.
