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