This review contains discussion of plot points that may be seen as mild spoilers for "Avengers: Infinity War."
So here it is: the "most ambitious crossover event in history," the grandest episode to date in cinema's most expensive soap opera — and, coming in the wake of "Ready Player One," the second most exhausting game of spot-the-reference you're likely to sit through at the movie theater this year.
Surfing a wave of hype and hubris, "Avengers: Infinity War" pitches the combined denizens of the Marvel Cinematic Universe — about two dozen, at the last count — against a genocidal alien named Thanos. He comes from a planet called Titan, wants to wipe out half the universe, and also has a very big chin, but he's not nearly as formidable as the Marvel Studios machine itself.