Freddi and Luther have very rounded bodies in this game, yet their bodies turn more "pointy" in the sequels.
When we see the Deep Canyon from "outside," it is about as wide as the screen. When we see it from "inside," it is much narrower.
When Freddi grabs the colorful shell, it is slightly smaller than she is. Herman's glowing shell is almost four times her size. Yet when she trades the colorful shell for the glowing shell, it is the size of the glowing shell. Furthermore, when she uses the glowing shell in the caves (if one of the bottles is in the caves), the glowing shell is now smaller than she is.
The sharks refer to Freddi's Grandma Grouper as "Grandma" Grouper. Luther does the same thing, however, since he is Freddi's best friend, it is more understandable.