Fifty years on, the dedicated and possibly psychotic fans of BBC's Doctor Who are going strong, and on Saturday gathered to celebrate the classic series with an anniversary special simulcast in 75 countries across the world.

Expectations were high going into the the show's 50th anniversary episode, called "The Day of the Doctor," that promised to answer some of the complicated series' oldest questions. After spanning three different time zones, reintroducing a handful of old doctors, even more old characters and destroying and then saving an entire planet, head writer Steven Moffat, the poor soul tasked with appeasing the show's fans, has done it. "We needed a lot — and, for the most part, we got it," writes Hitfix's Liane Starr

The episode centered around a key point in the show's extensive history — the fate of the planet Gallifrey. Not everyone was impressed with the execution, of course. The Guardian's Viv Groskop took issue with the 120 minute episode's scattershot storytelling — the three time zones likely played some part in that. But Starr praised Moffat for his ability to alter the Doctor Who continuity with grace: 

That Moffat manages to change this result (and yet not change the Doctors' understanding of it) is a great reward that alleviates some of the darkness we saw last season but doesn't rob the show of the more sophisticated throughlines we've grown used to seeing. It's really only when you watch early episodes of the show, specifically Christopher Eccleston's Ninth Doctor, that you remember that the show was once more of a rip-roaring good time, with more of an emphasis on adventure than dire, lasting consequence.

One universally loved part of the 50th anniversary episode was the onscreen chemistry between the 11th and most recent doctor, Matt Smith, and his predecessor, David Tennant. The Telegraph's Ben Lawrence explains

Tennant is edgy and mercurial, likely to turn on a pin. Smith is gentler, with a boyish eccentricity and other-worldly strangeness. They sparred terrifically with a fair amount of trademark humour. 

Moffat can breath easy knowing Doctor Who fans aren't about to knock down his house and demand their money back. The loved it. On Twitter — the cultural judge, jury and executioner — fans shared their immediate reactions, and they were (mostly) positive: 

Now Moffat can turn his attention towards the show's annual Christmas special, where he'll handle a transition from one Doctor to the next. Smith will pass the TARDIS to Peter Capaldi, who, keen-eyed fans may have noticed, made a very brief debut in "Day of the Doctor."