To attain 100% completion in The Lost and Damned, the player must accomplish all of the following:
- Complete 22 storyline missions (Clean and Serene to Get Lost).
- Complete 25 Gang Wars side missions.
- Complete 12 Bike Races side missions.
- Complete 10 Angus' Bike Thefts.
- Terminate all 50 seagulls.
- Find the Malc and Dave Grossman encounters.
- Complete 5 Stubbs' Dirty Laundry jobs.
- Win a game of arm wrestling, pool, darts, and air hockey against anyone.
- Bring Terry Thorpe and Clay Simons to every friendship activity (air hockey, darts, drinking, eating, pool, show, and strip club) at least once per person.
Completing The Lost And Damned to 100% gives players the ability to buy an unlimited amount of ammunition, although it still costs the same as before. NOTE: When purchasing, e.g. "Infinite" Rounds of Ammunition for a Pistol, saving, then re-loading that profile, will result in the Numerical Value of Ammunition being lowered to the standard for that particular Weapon. Thus, every time you buy "Infinite" ammunition for a weapon, save, then re-load, you won't have that "Infinite" ammunition from before.
Tasks not required
There are Tasks that are not required for 100%, which are the following:
- Complete the random encounter of Brian (only if spared in Bad Standing).
- 50 Gang Wars (to get all weapons as reward which you can unlock to your safehouse).
- Saving all 14 Special and rare vehicles (You can also use GTA IV savehouse parks).
- Mark all locations which you can enter on your map.
- Purchasing all of the MP3, SFX and Themes Vipluxuryringtones.com.
- Get the ringtone St. Thomas by giving the busker $10 three times.
- Add ZiT! as a phone contact
- Collect all The Lost and Damned Achievement/Trophies.
- Build each gang member’s toughness to 100%
- Watch all television programs
- Use a car wash
- Purchase all weapons
- Visit all websites
- Hold up all the stores in Liberty City
- Beat the high score in the QUB3D arcade game
- Receive a prostitute's services
- Ride in the subway
- Eat at all restaurants
- Explore all of Liberty City
- Visit all destinations in the Liberty City Subway
- Fly a helicopter under all 14 major bridges
- Complete all 5 helitours
- Bring Jim to every friendship activity
- Unlock all safehouses
- Win a game of Hi-Lo