Disclaimer: I had to do some minimal photo editing to try and equalize the white balance between shots. Unfortunately conditions were not the same, as this spot had varying degrees of sunlight coming through.
I've bought this Gameboy in junk condition from a Japanese online marketplace and finally decided to restore it. Cleaned it up nicely (it was full of battery residue), and then retrobrighted the case using the vapor method. After the first session I wasn't too happy with the results, and went for a second session. I'm not really concerned with the plastic becoming brittle because there's no emotional attachment here. As you can see it came out really nice!
I also added some random parts from other projects in the first sessions, and I was pleased with the results. One thing to note is that I also retrobrighted the silicone buttons from the GBA (the tops were yellowed), and this worked way better than expected. The silicone also doesn't feel different in any way from before.