The term gimmick has a negative connotation, but it doesn’t have to. Gimmicks can work. When a gimmick is implemented appropriately it turns into creativity and fresh ideas. The key to making a gimmick work, I would argue, is it can’t be the crux of your idea, it has to be the twist. If everything you do is dependent on the gimmick then it is nothing more than the negative connotation is correct, but if the gimmick is the thing that changes your work then it can reinvent it and make cliche things seem fresh and new.
Happytime Murders is a gimmick film. Apply the negative connotation.
Source: Destructoid Review: The Happytime Murders