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