Bacall does well here - especially considering this is only her 2nd film. This one is often overshadowed because it falls between 2 great successes: "To Have and To Have Not" (1944) and "The Big Sleep" (1945), both of which paired her with Humphrey Bogart. Granted this one is not up to par to the other movies but I think through no fault of her own. I think there was some miscasting in having her portray a British upper-crust lady. No accent whatsoever. I think all the strange accents were distracting - Boyer was certainly no Spaniard. It was hard to keep straight which country people were from.
I really liked the black and white cinematography. Mood is used to great affect - I especially liked the fog scene. The lighting also does a great job of adding to the intrigue and tension.
Bacall is just gorgeous. Boyer just doesn't fit the romantic leading man role for me - so he and Bacall together was a little strange. Not great chemistry - and certainly no Bogie and Bacall magic. But I still really liked this picture. There is great tension and it moves along well enough. I must say I found the murder of the little girl quite bold for this period film.
Katina Paxinou and Peter Lorre stand out as supporting cast. Paxinou as the hotel keeper is absolutely villainous and evil in her portrayal. Her one scene where she laughs maniacally as Mr. Muckerji is leaving after exposing her as the child's murderer is quite disturbing. Lorre also does quite well in his slimy, snake portrayal of Conteras - a sleazy coward to the end. Wanda Bendrix also does quite well in portraying the child Else - especially considering this was her first picture and she was only 16 at the time (though she appears much younger). Turns out she later married Auie Murphy which proved to be a short lived, tempestuous marriage.