Here is the full list of all 33 Dark Data achievements.
10 Headshot Kills
250 Headshot Kills
1000 Headshot Kills
All Players in Match With 90% Accuracy
500 Jumps
Kill Three Players with One Rocket
Kill 10 Players while Health is Under 10
Kill 1000 Bots
Kill 500 Bots
Kill 100 Bots
Unlock Master Cheat
Squat 500 Times
Win against augmented bots without dying
250 Melee Kills
Play 10 Games in a Row
Play 25 Games in a Row
Play 50 Games Total
Play 100 Games Total
Use Every Weapon
Play Game with 4 Players and 4 Bots
Get 50 Double Kills
Two Double Kills in One Match
Get 10 Triple Kills
Get a 4+ Killing Spree
100% Accuracy During a Match
5 Hours Played
50 Hours Played
100 Kills
500 Kills
1000 Kills
Get 3 Kills While Crouching in a Game
Win 25 Hold Your Death Matches
Win 25 Capture the Floppy Matches