Well, what makes Sister Stella more Lacaba than de Leon is that it actually shows political activism, the only de Leon film to do so, and it wears its activism on its sleeve--again, the only de Leon film to do so. There is political subtext in many de Leon films, but it remains subtext--no speeches, no overt themes, and no speaking directly at the screen (again, Sister Stella is the only de Leon film to have this device).
Hindi Nahahati, on the other hand, shows a man manipulating a woman--a theme shared by Itim, Kisapmata, Bilanggo sa Dilim and even to some extent Bayaning Third World (Josephine Bracken, though this is only suggested, never shown). There is the suggestion of incestuous feelings (Kispamata, and in an indirect way Itim where father and son in effect share the same woman); the man is introverted, passive unless pushed too far, and does not like to reveal his motives (Kung Mangarap Ka't Magising, Kisapmata, Itim, Batch '81--heck, make that every de Leon film with maybe the exception of Aliwan Paradise).
And even in other aspects the film is distinctly de Leon--the acting, which is consistently understated (and one of de Leon's--Christopher--finest performances); the cinematography, which is realistic and unshowy, yet intelligently staged and lit; the flashes of brilliance--the crystal swan, Edu Manzano's death scene, so on and so forth.
What's so interesting is that it's still recognizably a komiks story--plenty of confrontations, an intricate plot, a melodramatic music score--but one heightened or enhanced by de Leon's sensibility. No name on the credits? No problem--de Leon's hand can be seen on every frame.
