It’s what we didn’t see in Ridley Scott’s first Alien film that made the sci-fi monster so exquisitely scary. The deadly game of hide-and-seek between mystery predator and the hapless space crew played on our nerves to incredible effect. But with each sequel, that power of omission has suffered serious diminishing returns, culminating in Alien: Covenant, which has nothing left to hide. Still, Scott succeeds somewhat in keeping his suspense mojo moving with new types of critters — parasitic, plant-like spores and a smooth, white, humanoid version of the classic black and scaly killer. Settings in foggy wilderness and dark ruins add legitimate spookiness. And imminently watchable Michael Fassbender as two versions of the same “synthetic” is the gravity that holds the whole bloody thing together.