“Guardians of the Galaxy, Vol. 2” gleefully triumphs as the best Marvel movie so far.

It begins with an endearing main title sequence featuring Baby Groot dancing to ELO’s “Mr. Blue Sky” and only gets better from there, as the Guardians face an unlikely villain who threatens the very fabric of the universe. Humor and action are a given, but the film surprises with a character-driven story marked by introspection and sadness.

Tuesday’s bountiful Blu-ray offers welcome contributions by director James Gunn, including feature-length commentary and an intro. Other highlights include a 38-minute collection of making-of featurettes and a gag reel (of course).

Also coming Tuesday

• “Jessica Jones” (Season 1)

• “Scales:  Mermaids Are Real”

• “Kill Switch”

• “Supergirl” (Season 2)

• “The Walking Dead” (Season 7)