Is there a requirement to make the game in 2D? Or can we do 3D?
I understand your answer you want clean 2d platformer game based on your assets.
But sorry I will go off topic and just add something about using 2d assets in 3d or partially 3d game (not related to this gamejam). I present to you "Four Game Developers, One Art Kit" YouTube series by Miziziziz
Four Game Developers, One Art Kit
not all of them are 2d assets in 3d game, but a lot of them are. Very interesting series on using same assets in different and original way.