L.A. Noire Cheats

The Third Degree (30): Correctly branch every question in every interview in a single story case.
The Hunch (30): Use four intuition points in a single interview session, correctly branching each question.
Auto Fanatic (30): Drive every vehicle in the city.
Hollywoodland (30): Find and inspect all gold film reels.
Auto Collector (15): Drive 40 different vehicles.
Keep A Lid On (15): Complete a brawl without losing your hat as an LAPD Detective or Investigator.
Auto Enthusiast (15): Drive 5 different vehicles.
Lead Foot (15): Keep the needle above 80mph for more than ten seconds while driving.
Miles On The Clock (15): Drive more than 194.7 miles.
Magpie (80): Find and inspect 95% of all clues.
The Shadow (15): Tail a suspect without being spotted, in a single case.
Roscoe And Friends (15): Kill at least one bad guy with every gun.
Wooden Overcoats (30): Bring down a total of 30 bad guys with head shots.
Dead Men Are Heavier (15): Shoot and kill a total of 100 bad guys.

L.A. Noire: A Slip of the Tongue Achievements
Chop Shop (20): During the Industrial Street raid, kill a goon by shooting the hanging engine block.
Femme Imbécile (20): Correctly branch every question in the interview with Jean Archer.
Nowhere In A Hurry (20): Catch and arrest Cliff Harrison before he is stopped by uniformed backup.
Racing For Pinks (20): Find and inspect all of the Marquee-printed pink slips.
The Printer's Devil (20): Complete 'A Slip of the Tongue'.

L.A. Noire: The Naked City Achievements
A Good-Looking Corpse (20): Find and inspect all of the narcotics in Julia Randall's apartment.
Chauffeur Service (20): Escort Heather Swanson to Arnett's apartment without damaging your vehicle.
Eight Million Stories (20): Complete 'The Naked City'.
Fakeloo (20): Tail Henry Arnett from Hollywood Station to the pawnbroker and travel agent without being spotted.
Give My Regards (20): Shoot every letter down from the tower at the Broadway Hotel.

Nicholson Electroplating Disaster Achievements
Bulletproof Windshield (20): Kill the drivers of two of the MP vehicles in the Hughes Aircraft gun battle before they pull up.
Out Of The Frying Pan (20): Pursue Vernon Mapes from the burning house to Hughes Aircraft on your first attempt.
Skeletons In The Icebox (20): Find and inspect all clues inside Okamoto's ransacked apartment.
The Big Unfriendly (20): Complete 'Nicholson Electroplating'.
The Nose Knows (20): Find and inspect the prop spinner at the Nicholson blast site.

Unlockable Outfits
Different outfits are available for unlock while progressing through the game

Beat Cop Uniform: Awarded for starting Beat Cop missions
Button Man: Awarded from the Badge Pursuit Challenge
Chicago Lightning Suit: Awarded for joining the Rockstar Social Club
Golden Boy: Awarded for reaching the Traffic Desk
Hawkshaw Outfit: Awarded after reaching rank 18
Sunset Strip Outfit: Awarded after reaching rank 8
Sword of Justice Outfit: Awarded after reaching rank 3
The Broderick: Amazon Pre-Order bonus
The Outsider Outfit: Awarded after reaching rank 13
The Sharpshooter: Pre-Order bonus from Best Buy and Zavvi

The Badge Pursuit Challenge: Unlockable Outfit
Different outfits are unlockable for Cole with some having benefits and others just appearance.

Button Man - Carry extra ammo for all weapons: Complete the Badge Pursuit challenge