Here is the full list of all 34 Insanity's Blade achievements.
The taste of true defeat
Beat the game on Casual difficulty
Pay your dues to the zombie priests
Wow! 100% on all your saves!
Reach the max level!
You beat the game!
Get hugged by a crawler
Collect all the questy things!
Play within punching distance!
Thurstan gets possessed
Bought the 6-way magic daggers!
Get all the pointy things!
Die in the water
Beat a walking level without crouching.
Get the Cock Puncher
Revisit the How To Play video
Use a continue on Stage 0
Set a hostage free
Rip an arm off 'em!
Go corpse surfing
Tear 'em in two!
Now you can throw daggers!
Throw 'em around!
Skip the How To Play Video
You are an ARCADE MASTER!
Upgrade Finn's axes to max level!
You like to live dangerously, no saves!
Go through HELL with no saves!
Hey! We thought you liked it rough!
Deliver a punishing ball kick!
Play singleplayer on the day of love
Play co-op on the day of love
Complete the Arcade adventure!
Finish Stage 0 in Hell Mode