Hi, 
Background: I know that we are not supposed to work beforehand in the code of the project, but I will only be able to work on it during weekends, meaning I will work around 4-7 days for this submission.
The actual question: Can I extend a project I worked on last weekend (submission for the minijam61)? 

Thanks!

-Sol

You shouldn't be creating anything specific to this jam prior to this jam starting. But you can use previously-made content (either made by yourself or by others) that wasn't specifically for this jam, as long as you mention what you re-used when you submit (so that others can rate your game fairly).

So in answer to your specific question: no - but you could treat it as a separate game and just re-use things from your previous game (if you mention these things upon submission in the appropriate text box).

That is very clear, thanks Xavier!