Here is the full list of all 50 Overload achievements.
Finish the Cronus mission in under 3 hours of playtime without saving
Break every monitor in the Cronus mission
Finish a Cronus level without picking up a single powerup (except keys)
Get 50 Challenge Mode kills in one session without firing a primary (secondary/smash only)
Fully upgrade every weapon and missile in the Cronus mission
Find every secret in the Cronus mission
Score 50,000 and survive to the end of all Challenge Mode Countdown levels (Rookie or harder)
Get 1000 kills in Multiplayer
Get 500 Challenge Mode kills on Rookie
Finish the Cronus mission on Insane
Win 25 matches in Multiplayer (matchmaking, team or anarchy)
Survive to the end of Countdown (Ace or harder)
Destroy an operator using only Flares
Finish the Cronus mission without upgrading anything
Get 100 Challenge Mode kills on Insane
Finish a Cronus level flying only backwards (no sliding or forward movement)
Complete Challenge Mode Countdown with 0 kills (Rookie or harder)
Die 1000 times in Multiplayer
Finish New Game+ (Ace or harder)
Complete a Cronus level without killing any operators (Rookie or harder)
Get 40 kills in each secret level in the Cronus mission
Kill yourself with a devastator 10 times
Complete the Cronus mission (Trinidad ending)
Get 100 kills in Challenge Mode Countdown (Hotshot or harder)
Get a kill with every weapon and missile in Multiplayer
Get 100 Challenge Mode Infinite kills on every level (Rookie or harder)
Finish 10 matches in Multiplayer (matchmaking)
Finish the Cronus mission on Ace
Get 500 Challenge Mode kills on Trainee
Score 100,000 in Challenge Mode on Ace
Complete Phoebe Refinery without using the Headlights or Flare
Finish 5 Cronus levels without finding any secrets
Unlock all the Challenge Mode and Multiplayer upgrades and loadouts
Smash 10 operators in one level
Get 100 kills in Labyrinth
Get 20 consecutive Challenge Mode kills without taking damage
Complete the Cronus mission without using the Hologuide at all
Destroy every operator in a Lockdown without taking damage (Rookie or harder)
Score 100,000 in Challenge Mode on Hotshot
Finish the Cronus mission on Hotshot
Max out all secondary ammo at the same time
Recover every cryotube in the Cronus mission
Score 100,000 in Challenge Mode on Rookie
Complete the Cronus mission (Beale ending)
Complete the Titan levels
Give the Hologuide a command in 5 different Cronus mission levels
Destroy 1000 operators
Complete the Outer Moons levels
Kill every operator on Ymir Outpost
Complete the training mission