THIS IS GORGEOUS! the chiptune and other instruments play off each other so well, and it strikes a perfect balance of having a really striking and memorable melody and being really atmospheric (I guess that's a good word for it? I mean the combination of instruments creates a really strong kind of soundscape).
also like everyone else, this reminds me of celeste, though it has it's own style going on, with the chiptune moreso emphasizing a sense of nostalgia, even if that wasn't intended. If you were going to expand on this soundtrack, it might be interesting to emphasize that aspect in the mixing and instruments used.
Also I think the mix could use a little more lower-end frequencies but that's the only real definitive criticism I have. Beautiful