Ok This is all gonna be in secret text so don't highlight if you don't want to know:
OK, I believe I am in chapter 3 (I have been on LOTS of sewer pipe areas under the city). I am at the part where grodon drops out of a pipe and onto a massive stacked pile of barrels. There are a lot of those little flying things in the room and there are a crap load of explove barrels. I have killed everything, but I don't know what to do next !!!