I had already made a game regarding time in my previous jam which ended 3 day ago, can I upgrade that game a little bit and submit it in this one? Because I'm a student I don't get a lot of time making games I only do it in Sunday's
Games published before the start of the jam aren't allowed because the submission page would become full of spam and promotion. Hope you understand. But don't feel pressured to work on your game for a full month, you can make it the last 3 days of the jam and it'd still count. The jam is not competetive after all.