During the development of Resistance 2, one of the things we decided we wanted to do was improve our lighting model toward more of a focus on runtime light performance. With deferred rendering all the rage, we certainly considered it. But ultimately we thought it both too large and too risky for our development process. So we went with a kind of semi-deferred model that allowed us to get much of the benefit of fully deferred rendering without having to completely re-write our pipeline. Mark Lee (Master Engine Programmer) explained the approach during a presentation to the programmers.