Here is the full list of all 50 Velocity 2X achievements.
Complete level 50
Use double the firepower!
Destroy 2500 airborne enemies
Unlock all abilities
Rescue 6,000 Jintinda
Destroy 50 Vokh Guards
Teledash through two Vokh at the same time
Shoot 5,000 pieces of glass
Collect 5,000 crystals
Unlock a bonus level
Get stuck in a door
Kill every type of enemy (doesn't incude boss battles)
Disable three switches within 1 second
Gain above average XP in half the levels
Hit every speed pad in Level 25
Fly over your first speed pad
Defeat a Vokh
Disable two switches within 0.5 seconds of each other
Gain your first PERFECT medal
Survive the first encounter with General Glaive
Dock your ship for the first time
Get squished at the bottom of the screen
Look in every folder in Flight Computer
Complete a level without letting go of boost
Collect all data packs
Get 100,000 points in the credits minigame
Gain 25 PERFECT medals
Earn Gold medals on all Critical Urgency levels
Boost all the way through level 3
Collect 10,000 crystals
Unlock all bonus levels (25)
Shoot 10,000 pieces of glass
Gain 50 PERFECT medals
Get a PERFECT medal on all Critical Urgency levels
Complete all bonus levels
Perfect all speed levels
Complete all speed levels
Trigger a speed pad 4 times in under a second in level CU05
Avoid every speed pad in level CU02
Boost and sprint all the way through level CU02
Destroy 6 turrets in level CU04 in under one second
Perfect all Dual Core Levels
Complete all Dual Core Levels
Perfect all Speed Runs
Race through Level DC02 without letting go of boost!
Die by leaving one ship behind
Destroy 16 turrets in 2 seconds in Level DC08
Play 60 different Daily Sprints
Obtain max crystals in 20 different Daily Sprints
Partake in your first Daily Sprint Challenge