There are 12 can pyramids to knock over in all, but you only have to knock over 5 for the achievement. Choose from this list below as to which 5 you want to knock over. To knock over, you of course simply have to shoot them... that's it.
1. Episode 1 – There is a stack on the fence to the right as soon as you get a gun and torch for the first time.
2. Episode 1 – After doing the “log puzzle” in the second part of the logging yard (after the river), there is a can pyramid at the top of the old stairs.
3. In Episode 2, after defending Lover’s Peak and falling down, then crossing through the bear trap infested woods, before crossing the next log crossing, turn around and walk to the cliff face overlooking the mill. It’s there on top of a barrel.
4. After getting the car in episode 2 towards the end, there will be a truck forked in the middle of the road, head left around it and when you come to the next truck, head left again. You’ll then see a bright light up ahead, head towards it and the pyramid is on the table ahead.
5. Episode 3, after escaping the radio station and getting to the first safe haven (with a generator), slightly further up the path is a shack with three lights surrounding it. In the farthest shack there is a can pyramid. Shoot it down for the achievement.
6. Towards the end of episode 3, after the silver mine and the cable car across the valley that crashes. It’s on the cable car station on the side that you’re travelling to.
7. Episode 4, in the gardens, after defeating the orderly and destroying a wheelbarrow and double gate with light, it’s on the wall by manuscript #63.
8. In episode 4 after you bash the barn door with the Viking ship (after the stage showdown), there are two pieces of hanging wire. There is one on the left of the second piece on a cylindrical wooden cable reel.
9. At the end of the floodgate puzzle in episode 5.