This was a pleasant surprise. My husband rented it, and I thought we were in for a kind of dull, droning PBS-sort of "talking heads" and "sleepy slides" documentary. Instead, "Blackbeard:Terror at Sea" is mostly filmed like a rather high quality theatrical movie, with a very professional cast, good costumes, sets and realistic ships. It compares very well with theatrical films such as "Master and Commander" or "Pirates of the Caribbean" in terms of look and feel.
Where it is lacking is in plot and back story -- they are rather thin. The film uses voice-over from a secondary character to tie together individual scenes, and some kind of lame plot devices (like the age-old "girl in boy's clothing" -- did this ever really occur? biological factors make it seem to me to be nearly impossible). But where the film shines -- and again, where it was most unexpected -- was in some excellent performances. The most notable of course is James Purefoy as Blackbeard: this is outstanding work. In a regular theatrical film, I think he would have been singled out for award nominations for this -- he's sexy and genuinely scary (and unrecognizable under all that beard). Blackbeard is the kind of role, especially in the light of Johnny Depp's indelible Jack Sparrow, that can either be done amusingly OR it can veer dangerously into parody -- it's all too easy for a "pirate" character to seem like something out of a Saturday Night Live skit. Purefoy neatly avoids either of these stereotypes and creates a genuine and believable and unforgettable characterization.
One oddity of the documentary (on DVD) was that Purefoy is the ONLY actor credited. I've never seen credits that did not mention the entire cast before and wonder why? The entire cast is excellent, and special mention should be made of Mark Noble for the role of "Mr. Hands", co-star and narrator; he is also very good.
Despite some slight shortcomings (such as: there are obvious edits designed around commercials, where scenes and dialog are repeated), this is well worth a rental, or even purchase. It's a bracing antidote to more humorous pirate films, or the sloppy sequels to Pirates of the Caribbean, and enjoyable for anyone who likes sea-themed movies such as Mutiny on the Bounty or Master & Commander.
I have renewed respect for National Geographic for producing something of this caliber -- it has the look of a several million dollar production.