A solid read all around; there are fun visual ideas and the use of the sprite is particularly good, even if the image editing is a bit messy, and the prose leans towards unaffected but does its job. The emotional climax works on a basic level and is wise to not focus too much on questions like how all this came to be and what happens next.
I think my biggest doubts have to do with the structure. Especially with the story being this short, I struggle to see a reason to give the game away so early in lieu of a more gradual buildup. The shifts between reality and fantasy start to feel a little repetitive after a point, and the ending is harmed, too; it's more difficult to buy the protagonist's arc about acceptance and moving on when the truth is relayed to the reader so bluntly and unambiguously. I think it could have been more fruitful to play up the denial just a bit more and linger in the uncertainty – the way the story works now, you're observing the character at a remove, but there is not necessarily enough psychological depth in him to make that super interesting.