Are we allowed to use a game we made before the jam started in the jam (without making any adjustments to the game)? Or do we need to either improve the game or make a new one in the jam?

Usually game jams require the game is made within the allotted time slot to provide a challenge.

Well I mean the game I made was made in like 6 days so it was within the time that the submissions will be open, so I'm not completely sure about it.

The purpose of most jams including this one is to make a new game within the jam timeframe. Our goal is also to encourage you to learn something new—the jam is a great community to do this and ask questions. If you want feedback on a previous game you’ve made in order to learn you’re allowed to share the game on Discord for feedback or critique.

Ok, good to know, thank you!