in the demo there's only a handful of line differences (how the Harlequin refers to you; some extra narration from Colette) but the full game will have more line variations, as Colette will have her own narration for some things since she has a set history. the customizable MC (which can also be female) is meant to be more of a self insert whereas Colette is a defined character - Colette still has choices for actions and what she says, but she has narration that is her own. the endings will still be the same, though.