For this scratch project, everything is working fine until i go to click a sprite that is supposed to change the backdrop to a maze. The maze is glitching a lot and not even changing the backdrop. All the sprites that are associated with the backdrop are showing too, just not the backdrop. Any tips?

Could you post or link to the project so we could see the scripts

I solved your problem - you were only missing a single script
In the bag you use to catch presents in the script that begins with when backdrop is pole553 - forever if score = 25 and so on you have to add a stop this script to the end of it as it keeps broadcasting Red Nose and switching the backdrop.