To unlock Bloody Hard Difficulty, complete Story Mode once.
To unlock Gang Bosses, do the following:
Andy Steele: defeat him in story mode
Asif Rashid: beat the Talwar Bros tutorial
Mason Grant: beat the Ec2 Crew tutorial
Morris Kane: beat the Morris Kane firm tutorial
Shan Chu Yang: beat the Water Dragon's tutorial
Zakharov: beat Zakarov's tutorial
To get Free Drive Unlockables, do the following in Story Mode:
Andy Steele: take over the Steele gang's HQ
Asif Rashid: take over the Talwar Brothers' HQ
Talwar Car: take over the Talwar Brothers' HQ
Andy Steele Car: take over the Steele gang's HQ
Mason Grant: take over the EC2 Crew's HQ
Morris Kane Car: take over the Kane Firm's HQ
EC2 Crew Car: take over the EC2 Crew's HQ
Morris Kane: take over the Kane Firm's HQ
Zakharov Car: take over the Zakharov Organization's HQ
Zakharov Character: take over the Zakharov Organization's HQ
Shan Chu Yang: take over the Water Dragon Triad's HQ
Yang Car: take over the Water Dragon Triad's HQ