This achievement is for destroying 50 barrels. Although the game is a rougelike and different each run, the beginning tutorial area is the same every time which means there will be 4 barrels directly in front of you upon starting. Aim at the barrel and press LT or RT (depending on character) to break it. Rinse and repeat. This achievement is cumulative so you can get it between multiple runs & characters. Also, if you want to make progress toward the food item achievements, make sure you press A to pick up the apple from the 4th barrel and then eat it using the DPAD button it correlates to. Once you break a total of 50 barrels you will get the achievement. Again, you do NOT need to destroy 50 barrels in one run- they can be done through multiple runs.