Here is the full list of all 31 Wimp: Who Stole My Pants? achievements.
Slay the enemy into the acid
Having died lose the ultimate roll
Die 5 times from the spikes on same level
Slay the enemy on the saw
Put out Wimp into the water
Score all rolls on Rusty Quest
Score all rolls on Cold Quest
Finish 10 levels with no a death
Solve the mortal puzzle with the help of teleporting
Stand 1 min in the water
Spend 2 min in the fire state
Destroy 5 explosive platform
Have a death from the enemy in Stony Chasing
Don't have a death from Stony
Get first roll at level 13 of Junk Quest in first try
Push the enemies into the acid at level 8 of Junk Quest
Complete the seafaring successfully
Have a successful descent on the rope at level 12 of Teddy Quest
Stick to the ceiling at level 9 of Junk Quest
Get first and second rolls with no death at level 15 of Junk Quest
Don't have a death at start in level 9 of Teddy Quest
Free the Stony at level 14 of Teddy Quest
Get two rolls in the same time
Don't have a death from the saws at level 6 of Rusty Quest
Accomplish Junk Quest
Accomplish Teddy quest
Accomplish Rusty quest
Accomplish Cold quest
Kill Boss at Junk Quest
Kill Boss at Teddy quest
Kill Boss at Cold quest