Here is the full list of all 18 BoneBone achievements.
Buy legendary weapon!
Buy 1 archer, 1 gunman, Tower level 3, Gun (player), Tower Gun, Crossbow
Buy tower level 3
Buy weapon with magic modificator!
Buy Gun for player
Kill 15 skeletons in the first wave
Buy Crossbow
Earn more than 5000 gold
Survive more than twenty waves
Save 10 refugee!
Buy 20 arrows for bow
Buy 5 archers
Kill 100 skeletons in one session of the game
Survive more than five waves
Hit at least once
The first time in a game
Buy 1000 hp for wall