The Legacy Cannon is a unique weapon that you can win if you successfully complete the game in Carlsbad Bay. To do this, go there at night and go to the right along the road at the side of the building with Yerva (the questioning machine). Kill the enemies and enter the large complex that opens. In the closed box is the cannon itself.
Pay attention to the map. The location of the crates is marked on it. The flashing lights indicate the crates that have not yet been opened. You need to get to them. Most of the boxes will be opened by your enemies. You have to open at least three on your own. One is on the tail of the plane, and all you have to do is kill your enemies and interact with it.
The other box will be inactive. It’s hidden in the second hangar, where Harriet is preaching. You need to activate all the levers one by one, in the right order:
The lever by the crate.
The lever on the other side, on the left (go over the plane)
The lever under the plane with Harriet standing in it.
Lever in the tail of the plane hanging in the center of the room (outside the plane, on the bridge)
The lever in the shadow on the right if you walk across the plane from the hangar’s starting point to the other side.
The lever on the nose of the plane in the center.
If you make it in time, you can open the gift box.
Finally, go back to the Yerva machine and walk up the path to the castle. Before the castle itself, turn right and go downstairs. Directly below the castle is a location with jungle decorations. Go inside by lowering the lever. You will have 3 minutes to determine the correct four-digit code.
Look for the first part of the code to the right of the code door. The vertical stick shows which position the digit is in, and use the circle with sectors to determine which digit it is. Look to the right and connect the two parts of the circle to find out the second digit. Go up to the second floor and go to the far right corner. Align two more parts of the sector. You know the three numbers. Go down and match one more digit. Just don’t forget the correct order.
When you activate all the gifts, go back to the building with the weapons. A door will open on the right. You need to go through it. Break the boards and disable the field neutralizer. Then activate the nearest lever. Quickly activate the next ones:
Run up to the far side of the room and climb up higher on the crates. Bypass the blue beams with shifts or maneuvers. Activate the lever on the top floor where you just went up.
Turn around, run forward, turn left, pass two obstacles and activate the lever in front (in fact, it is next to the previous one, behind the wall.
Turn around and run to the lever opposite, over the same two obstacles.
Turn around and go to the far left corner, to the first lever on the list. Go down and turn left to the nearest lever on this level. Activate it.
Do the same with the lever on this floor near the stairs that lead to the exit.
Follow the drawers up to the top floor again and get to the lever in the opposite corner. This is the last one. Although it’s not right in the corner, it’s exactly on the opposite side of the first lever from our list.
Now you can pick up the Legacy gun, one of the four unique weapons in Deathloop.