Here is the full list of all 20 Bodyrain achievements.
Kill 100 zombies
Kill 500 zombies
Kill 1000 zombies
Kill 5000 zombies
Kill 10000 zombies
Defeat the first boss
Defeat the second boss
Defeat the third boss
Defeat the fourth boss
Defeat the final boss
Beat the game
Purchase your first weapon
Purchase all weapons available
Purchase 10 grenades
Play 10 matches
Play 50 matches
Play 100 matches
Reach level 5
Reach level 20
Reach level 30