Romans Chapter 1—Sin of the basic immoral person, the person that wants to ignore God, His law and His principals and live however they please without much thought given to Who God is and What He demands.
Romans Chapter 2 (part 1)—Sin of the morally superior person. The person that try to find the high ground within the human condition. I’m not a murderer, I haven’t done certain things, I’m not as bad as they are.
Romans Chapter 2 (part 2)— Sin of the Religious person who may even practice the law and know the content of the law, but have only the letter of the law and not the heart of God through the redeemer, the perfecter of the law.
Romans Chapter 3— Continue looking at the hyper-religious person, and now specifically at the guilt of religious skeptic.