Here is the full list of all 25 Hooligan Vasja achievements.
Defeat the Catboss
Kill an enemy with falling balcony
Kill 3 enemies with one firecracker
Use a firecracker
Participated in a battle
Kill 5 enemies with 5 bullets
Break off a balcony from the wall
Kill 4 enemies with one firecracker
Kill 5 enemies with one firecracker
Finish a level without incurring any damage
Hit 50 cats jumping upon Vasja
Kill 500 grannies
Kill 250 gramps
Kill 125 neighbors
Kill 50 cooks
Kill 25 clowns
Defeat the Dogboss
Defeat the Trollboss
Defeat the Ratboss
Defeat the Clownboss
Restore 1000 HP
Manage to die while medikit is nearby
Kill any boss with the last bullet
Do not let a pigeon to be killed