Aqui está a lista de atividades que deve fazer para completar 100% do jogo:

Completar as 23 missões principais: (65%)
Clean and Serene
Angels in America
It's War
Action/Reaction
Liberty City Choppers
Bad Cop Drop
Buyer's Market
Politics
Coming Down
Off Route
This sh*t's Cursed
Hit the Pipe
End of Chapter
Bad Standing
Heavy Toll
Marta Full of Grace
Shifting Weight
Diamonds in The Rough
Roman's Holiday
Collector's Item
Was it Worth it?
Get Lost

Completar todas as Gang Wars, que são no total de 25. (3.33%)

Achar todos os Random Characters: (4.75%)
Malc - Primeiro encontro
Malc - Segundo encontro
Dave Grossman

Completar os "jobs" de Tom: (5%)
First Impressions
Knowing Me, Knowing You
When the Blue Chips are Down
Phone Ho'
Communication Breakdown

Ganhar os jogos com qualquer amigo: (5.25%)
of arm wrestling;
bilhar, dardos;
air hockey.

Levar Terry ou Clay para sair/jogar (5%)

Completar as corridas de moto: (3.34%)
Park Circuit
Holland
Alderney Beach
Alderney Casino
North West Alderney
Alderney City
Tudor Docks
Alderney Industrial
Bohan Steps
Bohan Strip
Bohan Beach
Schottler Station

Completar os roubos de motos de Angus: (5%)
Ex-Display
Short Stay Parking
Delivery Boy's Hardship
Stripclub Hog
Beachcomber
Get Off Your High Horse
Tattoo Parlour Lament
A Ride in the Park
Zorst Fumes
Take Out Liquor

Matar as 50 seagulls/gaivotas (3.33%)