Sabotage is an absolutely suspenseful film, like all of the other ones that I've seen from the Master of Suspense, Alfred Hitchcock. He always knew how to do a gripping film so amazingly.

Karl Verloc is the owner of a cinema and yet a member of a terrorist gang that is planning on doing an attack in London. He lives with his wife Sylvia and her little brother Stevie and they don't know about his double life. But things will not stay that way so much longer and with the help of the detective Ted Spencer, who is undercover trying to catch Verloc, Sylvia starts to suspect that something is wrong her husband.

Oskar Homolka, Sylvia Sidney, John Loder and Desmond Tester, all had solid performances, with a especial mention to Sylvia Sidney with such powerful facial sad expressions that perfectly showed the pain, that her character Sylvia Verloc, was living through. She didn't even needed to talk in some of the scenes for the audience can feel her pain.

The sequence before we got to the climax of the film is fantastic!

It's so interesting to see that considering this was made in the 30's, the subject of the film is so modern these days. Terrorism unfortunately is a terrible thing that the world had already the misfortune to witness many times.

I think I find Hitchcock's early British work to be mostly dull, although of course you can see the flashes of brilliance that would become his hallmark. Here, it comes most prominently in the [spoiler] bombing sequence that results in the death of a main character. [/spoiler] But the rest of the movie just doesn't add up to much: performances are stilted and awkward, the pacing is off, etc. I haven't read much about this period, but I wonder if he didn't have access to the same technology as he would have had in the States.

That's a surprisingly harsh plot for a movie from this era and the fact [spoiler] that they really showed the explosion and a young boy getting killed [/spoiler] surprised me.
Although it is rooted in the realm of spies, terrorism was something not known at the times, it bears a striking resemblence with events happening today.
Those old movies are sometimes really worth watching.