I'd like to just retract any negative comments I may have made about Overlord, in particular those relating to its story and the choices it provides you with. It turns out I shouldn't have passed judgement on those elements of the game before seeing the final levels, which are genuinely surprising and quite unexpectedly excellent. It's one of those rare cases of an ending retroactively redeeming everything that came before it.
Overlord's script and story are by game writer Rhianna Pratchett (daughter of Discworld author Terry Pratchett) and it turns out, now that I've seen the complete picture, that they're quite an achievement.
I'd heartily salute Ms Pratchett, but in the process of some quick research I've been made aware that she's also the perpetrator of Mirror's Edge's story, which she either completely bungled from the get go or allowed to be butchered by someone else in the development process.
Either way, as I figure it Overlord and Mirror's Edge cancel each other out, leaving her with a relatively clean slate overall.