"Brainless action" refers to an action that is done without thinking or using common sense. It implies that the action lacks intelligence or careful consideration. Full definition
Willis, so often the centerpiece of brainless action movies, reminds us again that he can be a subtle actor, as muted and mysterious as actors we expect that sort of thing from — John Malkovich or William Hurt, for example. (rogerebert.com)
Half Past Dead is a series of brainless action sequences interspersed with dumb dialogue and a thoroughly incompetent understanding of logic, courtesy of writer / director Don Michael Paul. (haro-online.com)
And in a movie season dominated by brainless action flicks and big explosions, Phenomenon is something magically different. (rottentomatoes.com)