Congratulations on finishing your very first game jam!
One thing I noticed in this short platformer from a design perspective, not a balancing perspective like e.g. speed of the moving platforms.
But at the section with the moving monster, you got one platform with where you could jump through from underneath, but at the very next jump the player collides with the very small platform. The problem here is there is no communication to the player that a shift of mechanics or rules is established. A simple fix for example would be a different texture for the unpassable platforms.
Its not game breaking here and probably won't be game breaking in any game, but it could lead to player frustration.
Nevertheless, great effort for your first submission!
Keep improving!