User blog comment:Themastercode1235/Will multiplayer ruin ME3?/@comment-3268946-20111208234556

The thing about the multiplayer is the fact that what it does is reward you in the main game by making you more prepared for the Reapers. It is still very much possible to reach the "best" ending and not even try multiplayer, it just gives you the chance to make reaching that a little easier, much like the double XP promotions for MW3. The difference being that you are rewarded for playing the game, not just drinking Mountain Dew.

P.S. A ton of games before have introduced multiplayer despite singleplayer still being the main focus, AC: Brotherhood, Dead Space 2, and Red Dead Redemption all had great singleplayer components, even with the inclusion of MP. Whether or not the MP components of those games are any good is a matter for another time. P.