"Oi, that's my horse!!!"
The Blackadder series has improved over time, and this case is proved most strongly in the first series. The Foretelling was the first Blackadder episode ever made, and possibly the least funny. The Shakespearean parodies were slightly screwed up, and could have been funnier and more mocking of the Bard. But this is the only episode of Blackadder that really grips you, especially towards the end, and does have a sense of mystery to it. However, this only helps you wonder - are you watching a light British comedy, or a dark historical epic drama? It only serves to make this episode slightly less funny.
On the whole, this episode could have been worse, but should have been better. It should have got a mere 5 for funniness, but the effects are much better done in this series than any other Blackadder (especially Series 3) series, and on the whole, it does slightly mock its own scary scenes, with Edmund's stupidity and daft voice. I therefore give it a 7 out of 10. However, if you wish to watch Blackadder for a laugh, not its dark side, you'd be better watching a later episode.