Will there be a lean left/right mechanic in FPS eventually?asked by Shane McCloud

Yes, it'll be a part of our cover system. I'm not in QA anymore, so it's very possible this could change, as everything does in game development. But what they were working on when I was in testing: you know in-game now, when you walk up really close to a wall, your character will hold his gun up. That was essentially putting you in the cover state. And then you could basically hold down the right mouse button and you would peek around whatever the nearest corner was. Or if you were crouched next to a railing, when you raised your gun and held down the right mouse button, you would peek over it. And so that was the lean mechanic that they had in at that time. And again, subject to change and evolve over time.