Here is the full list of all 23 Serious Sam 3 VR: BFE achievements.
Complete the game in single player on unmodified serious difficulty.
Complete the game in single player in the estimated time on each level.
Awake the Guardian of Time.
Use the Mutilator to surf after a Werebull.
Kill 20 enemies with the Minigun without releasing the trigger.
Power up the Timelock.
Blow a Major Biomechanoid into pieces.
Start the car.
Kill an enemy using the Mutilator.
Kill a Witch-Bride of Achriman.
Kill at least 5 headless kamikazes in one explosion.
Kill 5 Cave Demons while they're in air.
Complete any level in cooperative with at least 2 players.
Solve the riddle of the Sphynx.
Defeat the spaceship.
Gib 20 enemies from close range with a shotgun.
Secure the bird.
Rescue professor Stein. So to say.
Decipher an Egyptian text.
Complete any level in single player.
Find at least 10 secrets in single player.
Smash 20 Kleers with the Sledgehammer.
Find Sam's classic outfit