I have a lot of respect for this kind of minimalist storytelling. I thought the design choices you made were effective at getting the feeling of "isolation" across quickly, like the beginning where everything reminds Ned of Heather, and the montage of moments showing the relationship deteriorating. The choice you gave the player of whether or not to move on was poignant; maybe this is the choice we all face in our lives. I played through the "good" ending first, and it was nice to see Ned had such a supportive work environment. I was surprised at first when the choice to not move on simply ends the game, but actually that's great symbolism: either you make the choice to move on or it's game over. I liked the addition of the quotes, as well.
In terms of technical things: one feature I would have liked is to have the option to use arrow keys, since I prefer that to WASD when I'm not using the mouse. Also, there were a few cases where the sprite render order seemed off, like things that should have been behind were in front or vice versa. Also, there seems to be no way to exit the game during gameplay. It would be nice if the escape key could at least bring up a pause menu or something that has the option to exit.
Overall a simple story, but gave me some things to think about. Keep at it, I see a lot of potential!