As the summer swelters on — as I write this, it is a muggy 78 degrees long after sundown — my thoughts turn to blockbusters. It’s surely no coincidence that the biggest and loudest of our high-gloss spectacles are pushed out during the height of summer. Their promise has always been one of relief from sunshine and heat, of course — a dark theater, a gallon of iced sugar water — but also from the mental sluggishness that seems to come with the dog days. Just relax in your stadium seating, they say, and don’t sweat the details. Don’t sweat at all, in fact.

But if the release cycle is no great mystery, there is another oddity to blockbuster success: what it can do for (and to) the career of an actor. In particular, consider the case of Chris Pratt. The actor was waiting tables and next to homeless when he was discovered at a Bubba Gump Shrimp Company restaurant in Hawaii — a semi-famous customer cast him in her short film. After years of other small roles, his long run as Andy Dwyer on television’s Parks and Recreation led to bigger invitations, culminating in unexpected success in 2014, during which Pratt starred in two of the year’s three biggest box office hits: The Lego Movie and Guardians of the Galaxy, where he played opposite Bradley Cooper’s raccoon bounty hunter.

Starring in two of the year’s biggest moneymakers — even if your co-star is a varmint — is hard to overlook, and so it is that Pratt, whose lovable character on Parks and Rec most closely resembled a Golden Retriever with a concussion, is now starring in Jurassic World, the fourth installment in Steven Spielberg’s ongoing dinosaurs-with-attitude series. As Owen Grady, Pratt is a dashing leading man who trains vicious velociraptors to follow his commands, only to find his command of the animals tested when a newly created dino hybrid is let loose in the Jurassic World theme park. There’s no doubt that Pratt is a star at this point. The more interesting question is — with such a varied acting history — just what kind of star he will choose to be.

For a different slant on the blockbuster phenomenon, look no further than Mission Impossible: Rogue Nation, which features Tom Cruise reprising his role as IMF agent Ethan Hunt for a fifth film. Cruise’s career has essentially been one blockbuster after another, even if not all of them have been successful. In this latest installment in the series, Hunt and his Impossible Mission Force (Ving Rhames, Simon Pegg, and others) try to dismantle a covert ring of spies before the CIA director (Alec Baldwin) can track the IMF to ground.

Also this week: In interviews for his stint in Jurassic World, Chris Pratt has called Jurassic Park — the first film in the famous series, released in 1993 — “kind of my Star Wars.” This week, Hadley’s Cinemark Theater gives filmgoers a chance to see what all the fuss is about when it screens the film in Sunday and Wednesday slots. Spielberg directed this first installment himself, which not only inspired Pratt, but a new generation of paleontologists to boot.

For a look at some slightly smaller animals, consider Amherst Cinema’s Saturday morning showing of March of the Penguins. Luc Jacquet’s 2005 documentary is a touching look at the hardships and triumphs of the Emperor penguins of Antarctica. Jacquet spent over a year at the South Pole filming the breeding habits of the penguins, and the result is alternately heartwarming and heart-wrenching, but it is always worth watching.•

Jack Brown can be reached at cinemadope@gmail.com.