[WARNING! LONG NERDY EXPLANATION INCOMING! TL;DR]
Basically, before the first frame update, the script checks if the boolean 'finalLevel' is true or false. If it is true, the gameObject attached to the 'worldCompleteBanner' variable (which should say "World _ Complete!" in-game once the level is completed) is set to be not active, basically making it invisible until the Player completes the level (there's a separate method for checking if the Player has completed the level).
If 'finalLevel' is false, it sets the value of 'worldCompleteBanner' to null, which (to my knowledge) forces the variable to be empty while telling the computer that it is okay for this variable to be empty.
This is so that once the final level of a world is completed, for a few seconds it can show "World _ Complete!", but if it is not the final level of the world it just proceeds to the next level. It always did that, but I made it set 'worldCompleteBanner' to null if 'finalLevel' == false so that every time I load up a level the Unity debug console wouldn't get filled up with errors something along the lines of "The value of 'worldCompleteBanner' in 'lvlProgressionScript' is missing!" or something like that (i don't remember the specifics of what it would say).
