It’s certainly more adult, according to the BBFC
The BBFC has certified various episodes (up to but not including the season finale we dare not name for fear of spoilerphobes) and features that will form part of the Doctor Who Series Six: Part Two DVD and Blu-ray box set, reveals Doctor Who News .
All the episodes from “Let’s Kill Hitler” to “Closing Time” have received PG ratings, except “The God Complex” (written by Being Human creator Toby Whithouse) which gets a 12. So does that mean it’s scarier than “Night Terrors” (which seemed to spook adults as much as children)? Maybe not. The BBFC doesn’t only award certificates on “horror” content, but on language and subject matter as well. Even a little more blood can tip the balance.
The BBFC has also listed a couple of the extra features – which would appear to be more “Monster Files” affairs. One is on The Antibodies from “Let’s Kill Hitler” but the other is a little more spoilery, so highlight to reveal: The Cybermats (or if you’re on a mobile device, click on next page… obviously, don’t click on next page if you want to avoid spoilers ).