PG-13, 159 minutes. Through today only at Mystic. Still playing at Waterford, Westbrook, Lisbon.

When Peter “Star-Lord” Quill, while inspecting a murky extraterrestrial region, pressed play on Redbone’s “Come and Get Your Love” in the first “Guardians of the Galaxy,” it would have been hard to imagine that James Gunn’s space opera would ultimately lead to something as sincere, poignant and kinda cornball as the trilogy-ending “Guardians of the Galaxy Vol. 3.” But as Gunn has showed over over the course of these increasingly soupy sci-fi spectacles, the genetically spliced DNA of his chaotic, cartoonish cosmic vision is a double helix of opposites. Breezy ‘70s rock papers over extreme violence. Cynical exteriors cloak sentimental emotions. A ragtag group of outcasts, more so than even the cast of “Fast and the Furious,” talk a lot about “family” and “friends.” Against the odds, “Come and get your love” has turned out to be a legit invitation. “Vol. 3” is a messy, overstuffed finale. But you rarely question whether Gunn’s heart is in it.