In the northern section of the Noventarmas region, you will discover a brewery with some great treasures. Completing this treasure hunt will give you the Into Orbit rocket launcher. Here is how you complete it.
Head to the upper section of Noventarmas. The treasure hunt is located near the water and also has a convenient anti-aircraft site nearby. Check the map below for reference.
When you reach this area, you will find an abandoned brewery. Head in through the front door to find the orange box with the note inside to start the hunt. The box is on the table next to the video camera.
Head through the door on the opposite side from where you entered the brewery. You will enter a room with a ton of tanks. A nearby note will tell you that the valves “should NOT be turned.” Well, you know what that means. Turn the valves.
There are four valves in total. The obvious one on the large tank will be turned last. Go under the stairs in front of you to find the first one. To the right of the stairs is the second. Run up the metal walkways and climb onto the piping. Follow it to reach the third valve. After all three have been turned, run back to the large tank and turn the final valve.
The large tank will explode, knocking you back, but also creating a hole in the ceiling. This part will also make you drunk. Look up to find a grappling point you can use to get up into the roof. Once up there, look to the left to find an air duct you can crawl in.
Crawl through the air duct until you reach the hole in the bottom of it. Drop down to land on a mattress. Turn around and you will see a small staircase that leads up to the treasure.