This is on the harbor level (just after the highway chase with the golden car). Not long after entering the warehouse you can't progress unless you operate a lever and raise a small box in the way. As soon as you cleared the obstacle enemies appear. You have to k.o. one with the box.
- Raise or lower the box (lowering the box this way won't deal damage!)
- Moving the box left or right
- Slam down the raised box (this damages enemies)
You only have to do one successful slam on easy to get the achievement.