Easy "Murderer" Achievement
Before smashing all the crates and particulary the one with the teddy bear on it, use your axe on the sheep after the cemetary. Only then you can smash all the crates that weren't necessary for the achievement 'Smasher' and for advancing in the story. Crates you need to smash to reach the sheep (and to use the axe)
Where you find the axe.
Where you began the game.
Easy "Smasher" Achievement
Locations of the crates:
Where you find the axe.
Where you began the game.
Four inside the hut.
With the teddy bear, after crossing the bridge.
The axe is broken after smashing the crates that are necessary to the story (where you find the axe, where you began the game and the one with the teddy bear), so make sure to break everything before smashing the one with the teddy bear (I suggest you to break this one last, especially if you're also doing Murderer, involving the sheep that you need to kill before breaking the axe - in other words, before smashing the crate with the teddy bear).