Casino Paradise Zone holds a few little nods to both previous games in the series and the real world. There is a welcome sign in the beginning of the level, which might be a reference to the Sonic the Hedgehog prototype and its welcome sign in Green Hill Zone. A platform resembling the "Barrel of Doom" from Sonic the Hedgehog 3's Carnival Night Zone is also present, and the background bears a strong resemblance to Walt Disney World Resort's Magic Kingdom at night.
Contributed by SonicManEXE
The invincibility theme from Sonic Advance 2 and 3 is present in the data for this game, despite using the classic invincibility theme from Sonic 1 and 2.
Contributed by SonicManEXE
Neo Green Hill's name may be a reference to the Sonic the Hedgehog 2 Simon Wai prototype. The prototype has a level named Neo Green Hill Zone, which is actually an early name for Aquatic Ruin Zone.
Contributed by CuriousUserX90