Here is the full list of all 45 Flatout 3: Chaos & Destruction achievements.
Win all Big Battle Arenas.
Win a Big Battle Arena match.
Win all normal Battle Arenas.
Win a normal Battle Arena match.
Complete all challenges.
Complete all stunts.
Win a Nightmare stunt.
Win an Industrial stunt.
Win a Golf stunt.
Complete 25 challenges.
Win all Speed tracks
Win on a Speed track.
Win all Monstertruck challenges.
Win a Monstertruck challenge.
Win all Utah Offroad races.
Win all Offroad races.
Win all Kansas Offroad races.
Win all Nightshift races.
Win all races.
Win all Uranium Mine races.
Win all Harbor races.
Play a multiplayer game.
Win all Vienna races.
Win all Outdoor races.
Win all Rome races.
Win all Detroit races.
Win a race.
Win on a reversed track.
Win a Nightshift race.
Finish a Nightshift race as loser.
Kill 10000 zombies.
Complete a challenge.
Score a 150 hit combo.
Complete all splatout levels.
Score a 100 hit combo.
Drive into water.
Score a 60 hit combo.
Be destroyed by a train.
Score a 50 hit combo.
Get a score of 7 million.
Score a 40 hit combo.
Score a 30 hit combo.
Score a 20 hit combo.
Score a 10 hit combo.
Kill one zombie.