A pretty cute experience overall.  It definitely had me laughing at times but you can tell this comedy simply comes from a different era.  Sure, it is clearly minded for a younger audience - the Master spending hundreds of years trudging through the sewers is a good example of that, but it also has a ton of jokes that really wouldn't fly for an all-ages audience these days, either.

In any case, it's great seeing Rowan Atkinson do a genuinely good job as a Doctor actor.  With the other regenerations along with stuff like McGann, John Hurt, and even the Shalka webcasts, there's definitely this sense in the fan community that there's a series of "lost Doctors" - actors who very likely would have had the role in the 90s during the Wilderness Era had the series not been cancelled.  I think, even though The Curse of Fatal Death is clearly a silly parody, they do take the source material just seriously enough we can get a real sense of what that show might look like, what sensibilities it would have had, and, given Moffat wrote this, a real sense of some of the aspects of production that would define Doctor Who in the future.  Any Doctor Who fan who really digs this sort of material should watch this at least once - it is a very interesting experience and short enough it doesn't overstay its welcome... at least not too much.