For me the page is displayed correctly. Maybe there was a problem on the page when you were trying it or some incompatibility with your browser.

For the submission of runs you must access the page of each world. For example: https://www.speedrun.com/duty_of_galaxy_lite_sokoban_ai_robot_push_box/level/World_1

By changing the last value in the link, you also have access to other world pages if you cannot access the page directly for some reason.