Yes you can update it as much as you want before deadline, "work with garage door open" if you like, but i think it's mb a bit unfair to do so during rating week. Except only for critical bugs. After the jam you can continue working on it again and mb participate in "Improve your game" jams.
p.s. i'm no authority on this jam but that's my general feeling about all jams
Exactly as Vimzim says here, and I also love "improve/finish your game" game jams too, working on a submission after the ratings close to make it more robust with more mechanics and fleshing it out can be fun. Game jams are super interesting things to take part in and for exploring new ideas. To then find out your submission idea was a something super fun to work on, and wanting to expand on it afterwards is great!
