Did you know? In Sonic & Knuckles/Sonic 3 & Knuckles, Sonic Team went to  a concerted effort to show that Knuckles’ story took place chronologically after Sonic’s.

This is actually evidenced by the lack of the Death Egg in the backgrounds of Knuckles’ stages - It had already established liftoff and was destroyed in Sonic’s story, hence it’s abscence.

Angel Island is also depicted as being in the air in Knuckles’ story. It is in the sea in Sonic’s as evidenced by Angel Island zone’s background differences between Sonic’s and Knuckles’ versions of the stage.