The conflict between the Tramp and the Drunken Millionaire is the major conflict of the film, turning on the fact that the Millionaire only recognizes and helps the Tramp when he is intoxicated. This misremembering leads to the conflicts that make the Tramp's life difficult.
The climax occurs when the Tramp sees the Flower Girl for the first time after getting out of jail.
The attempted suicide and subsequent saving of the Millionaire is played off as nothing important. However, it is very important.
Innovations in Filming or Lighting or Camera Techniques
A perfectionist, Chaplin shot the same scenes over and over again until he got everything he wanted right. Additionally, the film is one of the first "silent" films that integrated sound effects and a coordinated soundtrack.
Many of the Tramps' situations are paradoxical in that things that should be easy become difficult, and then sometimes, things that seem difficult are surprisingly easy.
City Lights Questions and Answers
The Question and Answer section for City Lights is a great
resource to ask questions, find answers, and discuss the novel.