The premise was quite interesting and it is always nice once in a while to have an episode not directed by a series regular director, one of not many episodes of 'Alfred Hitchcock Presents' for that to be the case. John Williams, in his third appearance of the series, was always worth watching, providing some memorable turns in for example 'Dial M for Murder'. Same goes for Alan Napier, best known to me as Alfred Pennyworth in the 60s 'Batman' show.
Season 1 had some very good and more episodes. The very difficult to rate and review "Whodunnit" to me is not one of them though. It is not a terrible episode by all means and has its moments, but it didn't really click with me to be honest. 'Alfred Hitchcock Presents' was no stranger to changes of pace and mostly did them well, but "Whodunnit" doesn't really do its premise justice and doesn't live up to its initial promise. As far as Season 1 goes, this is one of the weaker entries.
"Whodunnit" does have good things. Napier brings a lot of class and intrigue to his role. Also enjoyed the ironic and droll humour, along with the sophisticated and witty kinds when done well ironic and droll humour is great (less keen on the cruder type, which comedy today is full of). Hitchcock's bookending is typically fun.
It does start very well, intriguingly and humorously. It looks pretty decent. Did like the chemistry between Williams and Napier.
However, Williams is not at his best and this is one of his weaker guest appearances in a role that does not suit him. He does try definitely, but his character's pomposity is very overdone in the writing which made him impossible to connect with. Actually ended up not caring enough about the identity of the murderer. Have seen mixed views on the ending, to me it is more conclusive than has been said but it did feel rushed and took a while for me to get the head round.
Despite starting off promisingly, this promise is not kept all the way through. The rest of the story felt too over-stretched and it also came over as silly and muddled. The sets are on the sparse side and the direction is pretty run of the mill, getting the job done in an alright way but it doesn't ever feel distinguished or inspired.
Concluding, an odd one. 5/10.