(some spoilers here)
Deltarune only has Chapter 1 out as of right now. But let me tell you, it's amazing. By the creator of the legendary game Undertale, Toby Fox, brings you a whole new game, (Not connected to Undertale's universe).
Once again, Toby brings us an incredible soundtrack. From hard rock battle songs like 'Vs. Susie' to the catchy tunes, like 'Thrash Machine'. Each song reflects the scene or character in such great ways.
The characters, from the tough, 'Mean Girl' Susie, to the sweet, kind hearted Ralsei. Each character is so different from the other, yet have such impact on the game and yourself. Even how Toby brings back characters from Undertale, (SPOILERS) like Sans and Undyne, just as various NPCs.
There are lots of secrets and easter eggs here. Quite a few may lead to a certain mysterious man. If you have the patience to figure out how to unlock the 'hidden boss' I would totally do it, it's well worth it.
I've never looked forward to a game continuation like I have with Deltarune. If you haven't played, I would definitely reccomend it.