Here is the full list of all 30 Save the Ninja Clan achievements.
Die 50 times.
Kill 25 enemies.
Complete one secret.
Attempt a level 10 times.
Fall for it on level two.
Beat the first level
Kill yourself with your own weapon.
Attempt a level 25 times.
Beat level 4 with controls reversed.
Beat a level with an A+ time.
Beat 5 levels without dying.
Beat 10 levels without dying.
Beat the first boss.
Beat the second boss.
Beat the third boss.
Complete 10 secrets.
Die 100 times.
Unlock something.
Kill 50 enemies.
Explode 50 times
Find and complete the secret ending.
Complete all the levels.
Collect 15 Collectables.
Level 11, go to "prison".
Level 19, crash the game.
Beat half the levels.
Play Pong in the game.
Level 29, play as a scroll.
Level 25, ride a cloud.
Level 9, see a smiley face.