A decent film maybe, but an awful adaptation
I was so very excited about the film, since I have read the book a few years back, and loved it so much. I know that there are not many films based on books that are better than the original, but I had an impression that this was sometimes closer to a charicature rather than an adaptation.
The acting was a bit overdone, and I dont mean the accents only (even not being British I still could realise that they did not sound right). Anna Lee's performance was particularly poor, and quite a few moments were, even by the standarts of the 1940's, quite... how to say... cheesy? overplayed? There were some great performances (the parents, a few background characters). But just the fact that the rest seemed misplaced and did not feel Welsh at all kind of killed it for me. I dont mean the accents only, but the way they behaved, they moved. Hollywood is not known for historical realism you can say, but I could not enjoy it fully because of that. It didnt feel like a film about Wales, but a film about America pretending to be Wales. Th scenography was at its best, and the surrounding in general, and music, but the acting was certainly not.
How Green was my valley was quite a big volume, so I was not surprised to see how many subplots got changed/ommited, but it did look somewhat ridiculous at times to see some of them crammed into two minutes of film and then just cut off. (Or not shown at all, like how did Dai bano got blind in first place, or Hew's falling in love and first sexual experience which was a huge part of his growing up, a process that was also somewhat flattened and brought to absolute minimum).
It remains a good film, but maybe people who do not know the original it might be easier to enjoy it.
I think this is a great material for a film, and should be done once again, with the attention to the detail and do justice to the novel; the film needed a lot more depth than was present in the 1941 version.