There are a maximum of 10 Outbreak: Lost Hope Definitive Edition achievements (10 achievements worth 1000 gamerscore)

• 

  A Little Too Easy - 50 Points

  Cleared Story Mode on Easy Difficulty or Higher
• 

  Biohazard Containment - 100 Points

  Cleared Story Mode on Biohazard Difficulty or Higher
• 

  Joining Their Ranks - 50 Points

  You died.
• 

  Kill Them First - 50 Points

  Defeated a Zombie
• 

  Never Surrender - 150 Points

  Defeated an Enforcer
• 

  Perfectly Normal - 100 Points

  Cleared Story Mode on Normal Difficulty or Higher
• 

  Surviving the Onslaught - 100 Points

  Cleared Onslaught Mode
• 

  Taking Down the Horde - 100 Points

  Defeated a Reptile
• 

  They're More Afraid of You - 150 Points

  Defeated a Brute
• 

  True Nightmare - 150 Points

  Cleared Story Mode on Nightmare Difficulty or Arrange Mode