Here is the full list of all 22 Mega Overload VR achievements.
Reach and clear wave 10 without losing a life
Use every power up in one play-through
Reach wave 20 without using any power ups
Clear wave 30
Earn a score of 500,000+
Destroy 30 enemies simultaneously
Destroy an enemy with a rocket explosion
Flip 4 Elecro Fighters simultaneously
Clear a wave entirely before any enemy reaches formation
Destroy 1000 Bombers
Destroy 1000 Explosive Bombers
Destroy 1000 Electro Bombers
Destroy 1000 Psycho Bombers
Destroy 1000 Blasters
Destroy 1000 Explosive Blasters
Destroy 1000 Electro Blasters
Destroy 1000 Psycho Blasters
Destroy 1000 Fighters
Destroy 1000 Explosive Fighters
Destroy 1000 Electro Fighters
Destroy 1000 Psycho Fighters
Destroy 500 UFOs