Congratulations are in order! This wonderful little platformer not only has a well executed breadth of mechanics that allow for player expression in problem solving, while still being relatively challenging to find a solution, but it also just plain looks and sounds good, especially for a game jam submission.
Small annoyances can be noted, such as things on top of the square not moving when it moves, unlike all the other shapes, and having to cycle through characters in a constant order, rather than simply selecting one which you would like to use.
Those are all merely nitpicks, of course.
Well done!