Here is the full list of all 30 My Friend Pedro achievements.
Kill an enemy using a barrel
Get a 20x combo
Get a 10x combo
Break 100 crates
Jump through 10 windows
Kill at least 3 enemies with one explosion
Get a 50x combo
Kick a frying pan in to the face of an enemy
Kick a skateboard in to the face of an enemy
Kick a Gas Canister in to the face of an enemy
Stick a knife in to an enemy
Kill enemy by ricocheting bullet off frying pan
Juggle basketball 10 times without it touching anything
Flip 10 tables
Dodge 1000 bullets
Kick enemies 100 times
Kill 500 enemies
Kill 1000 enemies
Kill 2000 enemies
Get an S-rating
Get S-rating on 10 levels
Get S-rating on 25 levels
Get S-rating on all levels
Complete a level without firing a weapon
Finish chapter "Old Town"
Finish chapter "District Null"
Finish chapter "Pedro's World"
Finish chapter "The Sewer"
Finish chapter "The Internet"
Finish the game