You should !
I read the document, I don't have a lot to say on the first part, it's good to have a frame to find an idea. What I can suggest you is on the "finished by", don't htink it's a good approach for a game jam, you may want to use some priority instead: P0, P1, P2, P3, P4 (P0 is the most important). Like that you don't waste time to think of what to do next, and you think in advance at all the step needed to reach the goal and in which order.
Like that you try to put in P0 what is important to have all your team working correctly (in my game it was set up the scene and the parralax camera for example). Then in P1 what is needed to have a complete game loop (on my game it was to be able to display a scene at a window, to enter a code, to take an action and to have a consequence). and in P2 what make you game have content (for me it was adding more scene, make transition between them). After is polish, details (for me it was SFX, music, transitions scene, title, etc) I am habit to implement sfx, that's why I put it at the end, but it can be P2 or P1 or P0 for other.
with this method, you know that doing P0 and P1 ensure you a complete game. And after is only bonus to make it better for the end of the jam