Here is the full list of all 20 Oh...Sir! The Hollywood Roast achievements.
Finish the career as Dirty Potter
Use 3 Comebacks in one single player fight.
Win a Cliffhanger
Win a Roast losing less than half of your HP
Take 30 Pride points off your opponent with a single insult as a Single Star
Win your first argument
Finish the basic tutorial
Win a Roast in less than 3:40 minutes
Receive 15 Golden Parrots with one character
Have 3 characters receive 15 Golden Parrots each
Have 6 characters receive 15 Golden Parrots each
Receive 69 Golden Parrots in total
Finish the career as Marilyn Nomore
Finish the career as The Greasy Wizard
Finish the career as Chop Sue E.
Finish the career as Wisecrack
Prove victorious in a battle royale of CFOs
Use a 55 points hot burn playing as a Single Star
Finish at least 25 scenes
Finish at least 65 scenes