Level Fun is decorated like an eternal birthday party, full of balloons, cake, and confetti. It looks bright and cheerful, but anyone who touches a balloon or decoration here slowly loses awareness and turns into a broadly grinning "partygoer," becoming part of the party forever.
The heart of the horror is a trap disguised as joy. The fact that the threat approaches not as darkness or a monster but wearing the look of a celebration breaks down vigilance and breeds a deeper unease. It is the Backrooms variant where deceptive safety is the most dangerous thing of all.