There was a movie I watched a few years ago and it was anime aired on adult swim. I just remember they were playing on this game kinda like a vr game but no really. The game I remember was cross platform so everyone was playing it on their phones, consoles, and laptops. But I believe the ending was a whole family had to get on the game and destroy some sort of boss in order to save the world. Sorry for the little information, thanks though.
Sounds like Summer Wars
An AI (named Love Machine) takes over a VR world and the end of the movie involves the whole family of the girl helping her to fight it in the VR world to stop a satellite from crashing. (emphasis mine)
Realizing that Love Machine sees everything as a game, Kenji has the Jinnouchis confront Love Machine to play Koi-Koi in OZ's casino world, wagering their accounts in a desperate attempt to stop Love Machine. Natsuki wins several rounds, but gets distracted and nearly loses her "winnings".
However, OZ users worldwide enter their own accounts into the wager on Natsuki's side, which also prompts the guardian programs of OZ—the blue and red whales known as John and Yoko—to upgrade Natsuki's account. Natsuki wagers the 150 million avatars given to her in a single hand and critically damages Love Machine, prompting the artificial intelligence to redirect the Arawashi towards Sakae's estate. Kenji attempts to break into the probe's GPS, while Wabisuke disables Love Machine's defenses. After being revived and assisted by several of the Jinnouchi family's avatars, King Kazma destroys Love Machine.
Aired on Adult Swim in 2013.