Here is the full list of all 30 10 Second Ninja achievements.
Restart over 500 times.
Skip a cutscene.
Wander around a level for its duration without murdering anything.
Drop a falling block on an enemy's head
Toggle off the leaderboards OUT OF SHAME
Die over 50 times
Fiddle around with the settings.
Finish the first world
Go into the light.
Try firing your shurikens in a boss fight.
Finish a level with 0.03 or less from your next star rating (or 3 star the entire game)
Shots... Shots Shots Shots Shots - die on spikes five times in a row
Complete the tutorial.
Get your first star rating.
Press restart before the timer has even begun
Finish every world.
Finish every world with 3 stars.
Kill two enemies with one shuriken
Spend 5 seconds or more without touching the ground
Make an icicle fall on an enemy's head
Finish the second world
Finish the third world
Finish the fourth world
Finish the fifth world
Finish the first world with a 3 star rating
Finish the second world with a 3 star rating
Finish the third world with a 3 star rating
Finish the fourth world with a 3 star rating
Finish the fifth world with a 3 star rating
Finish Hard Mode and bleed the game dry for content