There are 10 milestones for 10 different statistics, as shown below. Every time you pass 5 different milestones, your character increases a rank, and when you pass all 100 milestones, you reach Perfect:1. Note that the Damage Dealt milestones are very low, so that the first few few ranks go by quickly. The highest Damage Dealt milestone is 90.0, which is 0.09K.

Thanks to AgentSam, who discovered these milestones/flags by analyzing the statistics of many different players. If you would like to have the milestones on your character analyzed automatically, try out my online calculator.