Are you sure? Did you use your dash? Many people have completed the game so I don't know where a jump would be impossible. Could you take a screenshot of the area you are talking about?
27 days ago(+1)
You need to use the dash ability of the characters to dash upwards which will let you get higher in order to clear the boxes. On keyboard hold "W" and press "Shift". On controller point the "left joystick up" and press the "right shoulder button".
Hope this helps.