Mass Effect 3 - How your choices determine the ending

PC Gamer chats with Casey Hudson about the impact of choices during Mass Effect 3 on the ending in a short, two-question interview:

PC Gamer: So it’s not like, if I let the Rachni live, now I can’t complete the game because they’ve killed everyone. But maybe I can’t get the ultra-nice ending where everything works out perfectly?

Casey Hudson: I think a way to think about it is if you made decisions early on, you’ll see them affecting this. And the decisions you might want to make that go against those prior things are gonna be harder. Killing the Rachni might present opportunities in Mass Effect 3 that you wouldn’t otherwise have, but if you don’t take those opportunities and you try and do something in opposition to that, then it would be harder for you than if you work with it. Similarly with the decisions at the end of Mass Effect 2, for whether you saved the base or destroyed it.

And so all the different things that you do, if you do a little side quest, or you go off and do a major plot, these things contribute to the war effort. If you just rip straight down the critical path and try and finish the game as soon as you can, and do very little optional or side stuff, then you can finish the game. You can have some kind of ending and victory, but it’ll be a lot more brutal and minimal relative to if you do a lot of stuff. If you really build a lot of stuff and bring people to your side and rally the entire galaxy around you, and you come into the end game with that, then you’ll get an amazing, very definitive ending.