The font definitely needs to be bigger. Even full screen I had a problem. Also the inconsistent text speed control was frustrating. I would come up with a universal control where while text is playing if you hold the mousebutton down it speeds up. Then once you get to the end of the text you have to release and then click to proceed to the next text. It is a balance between clickthrough and forced reading. If you are going to have a text only game more control of the text is necessary.
I would add more interactions beyond just find the question marks. Some sort of branching story or minigames would be a great addition.
Theme wise this game is excellent. It doesn't wallow as many depression themed games tend to. The use of the gray and the flashes of color are very relateable to my experience.
And of course, good job on the 3d modeling. It is a great presentation, and the occasional flickers of color do a great job of highlighting the breakthroughs.