Here is the full list of all 28 Serious Sam VR: The Second Encounter achievements.
Survive the storm on the Grand Cathedral.
Finish the Legend of the Beast campaign in single player or cooperative.
Complete the game.
Complete the game in single player by beating the estimated time on each level.
Complete the game in single player on unmodified serious difficulty.
Complete the Medieval episode in single player or cooperative.
Kill 100 Kleers with the Cannon.
Destroy an enemy cannon with your own cannon.
Complete any level in co-op.
Kill 10 enemies with the Chainsaw without releasing the trigger.
Earn a gold medal on any level in cooperative Survival.
Frag a total of 100 players.
Win a versus match.
Complete the Persia episode in single player or cooperative.
Kill 20 enemies with the Minigun without releasing the trigger.
Kill 200 enemies with the Laser gun.
Complete the South America episode in single player or cooperative.
Kill at least 30 enemies with a single Serious Bomb.
Kill 100 enemies with Serious Damage active.
Find at least 10 secrets in single player.
Burn 100 enemies to death.
Kill 20 Harpies with the Sniper rifle.
Use the Flamethrower on a Lava Golem.
Complete any level in single player.
Cut down some trees.
Earn a gold medal on any level in single player Survival.
Kill 50 Cucurbitos.
Find a secret under water.