“American Assassin” (**1/2 out of four) was a reasonably engrossing but lukewarm action thriller about a young hothead (Dylan O’Brien) whose girlfriend is murdered by Islamic terrorists while they are on vacation and is subsequently drawn into the world of the C.I.A. involving a counter-terrorism unit run by a former Navy SEAL (Michael Keaton) who mentors him as they try to team up and enact revenge and at the same time save the world. Film moves fast and features plenty of action scenes and has a spectacular action climax yet remains oddly aloof and never connects emotionally. Yet another “Bourne” wannabe that comes frustratingly close to working but yet falls short. Keaton is first-rate as usual.