How Much Does Mass Effect 3’s Multiplayer Affect Your Single-Player Ending?

Fans were a bit worried when BioWare announced that Mass Effect 3's online co-op mode would affect the outcome of the game's story. Followers of the traditionally single-player, story-driven franchise didn't want to be forced to play multiplayer just to get a halfway decent conclusion to a narrative they'd been invested in for the last five years.

Not so, BioWare assured us. They'd gone to great lengths, they said, to ensure that the single-player experience would stand on its own, and they told us we would be able to achieve the best ending without having to spend any time in co-op. 

Now that the game has finally been released, it turns out those fears were well founded after all. While it's technically possible to get the best ending to the single-player campaign without ever having to touch multiplayer, it's ridiculously demanding, requiring you to do every side mission and make perfect choices, including those that you import from the previous games.

See, the ending in Mass Effect 3 is based on how many War Assets you have. You can gain these during the single-player campaign by performing missions and earning the loyalty of various factions and races. Once they're on your side, their troops will be added to your tally, increasing the size of the force you'll have when you take on the Reapers in the game's conclusion. All good so far.

But here's where things get sketchy. Your War Assets are universally affected by your Readiness Rating, a percentage multiplier can only be upped by playing co-op. Don't touch the multiplayer, and all those hard earned allies will only be operating at 50% efficiency, making it twice as difficult to gather sufficient resources, and making grinding a practical necessity.

As if that weren't bad enough, the Readiness Rating is tied to specific regions of the galaxy, meaning that you'll need to play on a multiplayer map set in a specific location to upgrade the units you earned from that sector in single player.

In effect, the game forces you to: A. Grind in multiplayer, where you'll coincindentally be able to purchase in-game weapons with real money to make things easier; or, B. Grind in single-player, and run the risk getting a terrible ending even if you complete every quest and side-mission the game has to offer.

Not cool, BioWare. Not cool indeed.