There seems to be real chemistry between Conrad Veidt & Vivian Leigh in this movie, and that is what makes it so compelling. The cinematography is also rather sophisticated, and the music score is good. Fascinating portrayals of "society" nightlife of the era. The special effects are better than average, and the duel between the U-Boat and the Q-Ship is not something you see every day. Vivian Leigh is simply ravishingly beautiful in this picture, made two years before "Gone With The Wind." But as beautiful as she is, Veidt's performance stole the show for me, and left me wishing he had been in more talkies.