LOS ANGELES — The latest video game consoles can play Internet radio, Netflix movies and YouTube video clips. But Sony and Microsoft, gearing up for a blistering battle in retail stores this holiday season, are reassuring consumers that their consoles are very much about games, too.

That message was particularly forceful from Microsoft at the annual Electronic Entertainment Expo, or E3, game convention here, where the biggest companies in the games business show many of the products they will release later in the year.

A year ago, Microsoft was promoting its Xbox One as an all-in-one entertainment system for the living room, one that could play games and then seamlessly shift to let people watch television, and change the channels with voice commands. On Monday, though, Microsoft shifted the conversation decisively back to games, announcing a lineup of almost two dozen titles, many of them hard-core shooting games, to be released on the Xbox this year, including an anthology of classic games based on the Halo science-fiction shooter series.

“Our goal is to make Xbox One the best place to play games in this generation,” said Phil Spencer, the head of Microsoft’s Xbox business, who received vigorous applause when he declared that Microsoft would dedicate the event entirely to games.