You protected Callista's uncle, Captain Geoff Curnow

Kill or incapacitate an enemy who threw a grenade at you.

Encountered the Memorial Mob

Drove a Formula car.

Drove a lap of the Tsukuba Circuit in under one minute.

Clear all Ambush Camps, Infestations, and NERO Checkpoints in a single region

Die for the first time.

Pass through portal on the snowy mountain peak.

Craft a weapon or gear piece of 'superior' rarity or higher.

Overcome your ophidiophobia

Kill 10 enemies in a row using only Gauntlet after obtaining the Revolver

Finish the game on any difficulty.

Kill 20 enemies using the E-Combo