Here is the full list of all 56 Copy Kitty achievements.
Defeat 25 enemies using a sword!
Destroy 139 enemies!
Complete Boki's tutorial!
Complete Savant's tutorial!
Combo 50 enemies in a row in Endless Mode!
Combo 100 enemies in a row in Endless Mode!
Squish a bug!
Clear 4 waves in Endless Mode using only the Kitty Kick!
Defeat 10 enemies with the bunny gun!
Defeat 25 enemies using a drill!
Defeat 5 enemies using a flaming whip!
Beat wave 50 in Endless Mode!
Beat wave 100 in Endless Mode!
Defeat Yolomacho!
Defeat a Krijyl!
Clear Boki's final mission!
Clear Savant's final mission!
Create a good custom level!
Defeat 3 enemies with a single one of Boki's drill kicks!
In one combo, use 9 out of the 10 basic weapons! (They can each be a part of a combined shot, though.)
Get 50,000 points in Endless Mode!
Get 100,000 points in Endless Mode!
Get 200,000 points in Endless Mode!
Get 300,000 points in Endless Mode!
Destroy an enemy after you have died!
Blow up 3 enemies using one Exploder Exchikke!
Summon a dragon!
Defeat 10 enemies using Diabolic Portal!
Defeat a boss using a penguin!
Complete Marathon Mode!
Pop all the penguins using only your feet!
Defend the skyscraper while leaving it completely intact, with Boki!
Kick Captain Yolomo off his airship and into the abyss!
Reflect a squeaky missile!
Block a Cavitation Beam using a kick!
Defeat a ninja using a shuriken!
Use every one of Boki's combined weapons at least once!
Find the Fallen Angel in Endless Mode, and defeat it!
Die from something that only does 1 damage!
Deal the final hit to a boss in Endless Mode by jumping on it!
Beat every environment in Endless Mode!
Defeat 20 enemies using Omega Weapons!
Defeat Arikan!
Defeat Arikan on hard mode!
Clear World 10 as Boki on hard mode!
Clear World 10 as Savant on hard mode!
Defeat every Yoggval on normal mode!
Beat the game as Boki!
Beat the game as Savant!
Beat the game as Boki on hard mode!
Beat the game as Savant on hard mode!