In order to qualify for a Complete Raid ranking, you must record all trash in the instance as well as all 10 boss kills. Four Molten Giant deaths must be seen before Lucifron is engaged.
To learn more about how rankings work on the site, you can read the rankings guide. A rank with a dark gold background is considered "at risk", since it is using tricks that will likely be hotfixed at some point in the future. If an in-game hotfix is released, then the rank will be removed. Removed ranks have a dark red background.