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