The Mass Effect series certainly had some memorable characters, but how about levels? While it might be hard to recall them now, each level required an enormous amount of work to get right. If you've ever wondered exactly how much, this GDC 2009 presentation for Mass Effect 2 should prove very enlightening.
The almost one-hour talk from BioWare's Cory Andrusko and Dusty Everman provides incredible insight into the process behind Mass Effect 2's level design, which is a lot more involved than you might think.
Each one was crafted in phases, with the first being "narrative playable". As you might expect, the idea here is to make sure the dialogue (if any) and story make sense, as well as the general pacing of encounters.
This is followed by the "white box" and "orange box" phases. The first is a blocked-out version of the level with AI-disabled enemies, without cover and collision, while the "orange" phase adds in the collision and has enemies with full AI.
According to the presentation, this latter phase was based on Valve's methods for level design:
We have an "Orange Box" stage, which we did borrow from Valve. It was not from their great games, it was actually from a Gamasutra article they had before then, talking about a "collision-only" level.
Beyond making well-designed and fun levels, the process helped developers be more efficient. By having what was essentially three prototyping phases, gameplay could be locked down and tuned before artists began the time-consuming work of painting textures and building geometry.