From the site:
As software engineers, we spend a lot of time skimming, reading, making changes to code. The coding font that we spend 8 hours a day staring at has a lot to do with our productivity and comfort. That is why I created this gamified experience to help you find your true love of coding fonts!
By the time I got to the last 4 rounds I could barely tell the difference between them, starts to get pretty subtle with the ones I chose. Oxygen Mono and Source Code Pro I struggled to pick between at the end.
I had a similar experience. I ended up with Fira Sans Mono, which is funny because I use Fira Sans all the time.