There is an area that has to be opened up to knock down a hidden stack. Go through the level as normal but when you go towards the exit, dont leave. Instead carry on and you will see a red platform. Ride on it to turn it green then go back around, past the swinging axe then you will see a gap. Thats where the last stack is hit that and you should unlock the achievement. Ride up the ramp and go to the exit.
Thanks to M4G II TihMaX for the following video posted in the comments.