The President (Kevin James) listens to his old buddy Brenner (Sandler), and with the help of Admiral Porter they train 'the best of the best' in arcade machine tactics for the second attack - a Centipede game at London's Hyde Park.
The Seals are failing, so Brenner and his old buddy Ludlow (Josh Gad) take over the light cannons and save the day, defeating the giant centipede.
The aliens give them their next challenge - a giant game of Pac-Man on the streets of New York. The Arcade Machine team know they need more help - and they offer an early release, and other perks, to the 1982 Championship winner Eddie (Peter Dinklage). They fit out 4 Minis with light cannons, and the drivers are Brenner, Ludlow, Eddie, and the original Pac-Man inventor.
Pac-Man soon shows up. The inventor exits his car to try to reason with him - but loses an arm in a pixel attack. The others chase after Pac-Man, but he soon swallows a power pellet and chases them, chomping through Ludlow's car. Eddie takes two lives away from it, before crashing in the harbor. After Pac-Man gobbles another pellet, Brenner times it right so that his car is snatched just as the time runs out. The humans win this round, and they celebrate with a Ball, and receive Q*Bert as a prize.
Soon though the aliens announce that the humans cheated, and unleash Arcade Armageddon on earth. Violet's son finds Eddie's glasses with codes that he used to cheat to get a speed boost, and he admits he cheated in 1982 too.
The Arcade Machine crew are joined by the President, and they try to protect the people of Washington DC from attack. Ludlow faces up to the love of his life, Lady Love, and he wins her heart.
Meanwhile Brenner, Violet, Q*Bert and the President are beamed aboard an alien ship for the final showdown - a game of Donkey Kong. To rescue the hostages, and save Earth, Brenner has to look beyond the patterns and be a 'true' arcade machine player. He grabs the hammer, gets to the top and throws it through Donkey Kong. The pixel characters are defeated, but Lady Love disappears too.
Later at an award ceremony, the President announces he has made peace with the aliens, and Eddie admits that Brenner is the best arcade machine player in the world. Eddie has also won himself his dream scenario of Serena Williams and Martha Stewart (and a sandwich) back at his hotel room!
Ludlow is still heartbroken, until Q*Bert transforms into Lady Love ... and Ludlow announces that she's his fiancee.
One year later, they are proud parents of many baby Q*Berts.