Here is the full list of all 55 Serious Sam VR: The Last Hope achievements.
All perfect hard
All perfect serious
Unlocked the entire skill tree
All 5 gold medals
All 5 platinum medals
Complete a co-op game
Complete a mission on hard without taking any damage
All 5 bronze medals
All 5 silver medals
All perfect easy
All perfect normal
Activate money time
Activate invulnerability
Activate rage
Deploy a dummy decoy
Detonate a serious bomb
Complete all level 15 arenas
Complete all level 20 arenas
Complete all level 5 arenas
Complete all level 10 arenas
Complete a level 20 arena
Complete a level 15 arena
Complete a level 10 arena
Use the portable medkit
Unleash an army of domestic spiders
First platinum medal
First perfect serious
Fire the orbital stun field
Fire the orbital psi laser
Complete a level 5 arena
Fire an orbital laser storm
All 5 wood medals
All perfect tourist
Defeat the giant Swamp Hive
Deploy a defense turret
First gold medal
First perfect hard
Deploy a drone squad
Step into the arena
Defeat the Earth giant
Activate time stop
Defeat the Shaanti dragon
Defeat the giant anomaly
First perfect normal
Complete a planet without healing
Fire an orbital laser strike
First silver medal
Activate serious damage
First bronze medal
First perfect easy
Unlocked a skill
First wood medal
First perfect tourist
Defeat the giant mummy
Step into the battlecruiser Saratoga