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