Here is the full list of all 18 BoneBone achievements.
Buy legendary weapon!
Kill 15 skeletons in the first wave
Buy weapon with magic modificator!
Save 10 refugee!
Buy Crossbow
Buy Gun for player
Buy 1 archer, 1 gunman, Tower level 3, Gun (player), Tower Gun, Crossbow
Earn more than 5000 gold
Survive more than twenty waves
Buy tower level 3
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