Passable debut

Rating: 6/10 (7 August 2015)

Bad boy makes girl AI. Good boy likes girl AI. Girl AI demonstrates her sentience by pretending to like good boy so she can escape. Bad boy gets killed.
The film is pretty entertaining for the first half or so, if you buy its somewhat sexist stereotypes: (a) male computer nerds want nothing more out of AI than a sentient female sex toy; (b) a female AI's big goal will be to use her sex appeal to escape the clutches of her evil "dad" creator. Let's call it "lowest common denominator AI."
After about half an hour, plenty of hints have been dropped: the main female AI (Ava) states that her greatest wish is to escape and go people-watching at a street corner; a "hidden" but obvious second female AI cuts vegetables with a knife and is abused by her creator; other female AIs are locked in cupboards. At that point, it's clear that this will end with Ava free and watching people at a street corner, and with bad "dad" and his young nerdy helper either locked up for eternity, or knifed, or some such unpleasant fate. And that's exactly what happens.
On its way to that inevitable conclusion, the film manages to be pretty entertaining at times. There is interesting chemistry between the female AI and the nice but naive young computer nerd testing her. There is a cat and mouse game of young computer nerd and genius AI-designer: who can outguess whose next move better? There is voyeurism, and meta-voyeurism, and meta-meta-voyeurism, as there should be in any film about recursive self-programming code. There are AIs peeling of their skin to tip off humans. And humans who start to wonder if they're just a bunch of code and hardware covered by fake skin.
Things fall apart at the end. Why is one AI allowed to run around outside and use knives during the whole film, while Ava must be locked up? Surely better and safer ways can be found to test the sentience of the locked-up one. Has Ava thought about when the power of her "inductive charging" will run out at that street corner? And so forth and so on. A typical case of scriptwriting oneself into a corner, which I did NOT expect from Alex Garland: he may be a first time director here, but he's not a first-time script writer.
I give it a 6/10: OK to watch once, but I suspect the appeal of this film will gradually decline with viewers and critics. Stanley Kubrick managed a far more ambiguous and equally murderous AI in 1968 with HAL 9000. Even "AI," a project Spielberg took over after Kubrick's death and botched, is in many ways better than "ex machina." Neither of these films bothered with awkward exposition dialogue about what a Turing test is, and other low-brow conversation that is totally unlike what would be going on between two top computer guys on a project. There are plenty of other good AI movies and TV shows. Heck, at least "Mudd's Women," the campy Star Trek episode about a planet full of female androids, revels in its 1960s political incorrectness. So for now, there are plenty of better ex machina alternatives around.