I quite liked the change of pace for the Halloween theme but agree that the whole thing seemed a bit flat, presumably because of the two injuries.
I'll admit I'm not a huge Halloween fan anyway. I also had young children who hated the gore and jump-scares so we always had to endure the zombie-apocalypse type themes of earlier years with lots of fast forwarding through the hammy VT (that they thought were quite scary at the time).
So I agree with the PP who said that the producers may have been toning it down for the pre-watershed family audience.
It must be difficult for the producers if they are going to insist on having Halloween as a theme. They can either repeat the same few songs/themes (monster mash AGAIN), get even scarier and gorier, or soften it up.
I would prefer if if they just dropped it now. Perhaps do movie night later when the slebs have developed better performance skills and get a say in their own song choice?