The Musical is a bit different from the classic 2001 film. The musical for once expands the character's story, each Shrek movie has its own unique story and themes. However adapting these into one big musical allows for a deeper exploration of character arcs, relationships, and the humor that the franchise is known for. The musical has tons of references across all 21 tracks. including Gyspy, Wicked, Dreamgirls, Little Shop, A Chorus Line, and The Lion King!
The Fairytale Forest: The Fairytale Forest in this world is the diverse community of all the different characters from all classic fairytales. Soon be taken over by Lord Farquad
The Swamp: an unflattering area in this world where it belongs to a certain Orger (aka Shrek) it may be smelly, scary, and isolated yet Shrek finds it an oasis rather
Duloc: A practically perfect community where there's one style. It's very controlled by Lord Farquad and things in Duloc get perceived as uncanny/ oddly uncomfortable.
Fiona's Tower: A cozy isolated tower where Princess Fiona has been trapped for over 25 years. Protected by a fire-breathing dragon.
^ I found this very helpful with learning lore about all the Characters of Shrek! - Christopher E