Nagisa does not actually wear glasses in the game. Another character does, though, and I thought she'd look cute with them so I modded the glasses sprite to fit her face. The background is primarily made of a composite of two photos that I tried to get to look a little more like a game CG background so she wouldn't stand out quite as much and not just look like she's slapped on in the foreground, but I'm not sure I fully accomplished that. The chalk drawing of Nagisa is a heavily modded SD pic of her from the game with glasses added.

Buford said:
The background is primarily made of a composite of two photos that I tried to get to look a little more like a game CG background so she wouldn't stand out quite as much and not just look like she's slapped on in the foreground, but I'm not sure I fully accomplished that.

No, you didn't. There are quality issues and some minor technical issues as well:

Details

Advice

Recommendation

Thanks for the comments/criticism, I'm not really an artist and mostly just putz around with an image editor to see what I can get out if it when the mood strikes.

The wall and chalkboard are actually the same photo. The second photo was just of a blackboard texture with more damage that I used in the very center, fading out to the edges, to keep the board from looking too flat and plain.

I agree that the lower right edge of the board where it meets the wall and rail is a bit rubbish; a layer effect that I liked for the rest of the image kind of ruined the edge appearance and I didn't do much to try and correct it.

As to the red gradient in the bottom, I left that as-is since it reminded me a bit of old-school CG art that did have reduced color and the noise (paint scratches and dings in the wall in the original pic) gave it a little texture, but with a high color foreground I agree it does look a little out of place.

Personally I think you did a good job. The reduced color feel works really well.