I was wondering about this as well. James shared this in the wrap-up post:
Reviewing Submissions As the jam isn’t ranked, there is no official ratings period, or requirement that people look over submissions. In fact, with almost 700 games submitted, looking through them is a daunting task. If you have time, please consider browsing through the games and picking a few to read and review.
Itch has a built in ‘Submission Randomiser’ for the jam, which keeps track of games you’ve viewed, and will only show you games you haven’t reviewed yet. It’s actually a lot of fun to shuffle up and read a random game.