Here is the full list of all 31 Velocity Ultra achievements.
Complete a zone without letting go of boost
Hit boost 100 times in a zone
Discover at least one secret area
Discover all the secret areas
Complete Zone 18 without upgrading weapons
Complete zone 21 without rescuing any survivors
Get 140,000 points in the credits minigame
Beat the minesweeper minigame
Complete the reaction test minigame
Earn a PERFECT medal on Zone 10
Earn a PERFECT medal on Zone 46
Earn a PERFECT medal on Zone 48
Achieve above average XP on every zone
Earn a PERFECT medal on Zone 50
Reach Zone 50
Complete Zone 50
Complete the Smith's Challenge minigame
Destroy 5000 Zetachron ships
Earn a PERFECT medal on all Critical Urgency zones
Rescue every survivor
Earn a PERFECT medal for every zone
Collect every in-game award in Velocity Ultra
Because this player earned it
Use pulse bombs to gain 50 multikills
Smash 500 pieces of glass
Disable four switches in quick succession
Disable three switches in quick succession
Disable two switches in quick succession
Destroy 1000 Zetachron ships.
Destroy 500 Zetachron ships
Get trapped and killed by the scroll