To achieve the "Full Fire" achievement in Collapse Railroad, you can follow these steps:
Answer: Use the rocket launcher to kill three enemies in two places to achieve the achievement.
1. After entering the game, you need to go to the right room on the second floor of Chaolu Mansion.
2. After arriving, you need to go up the wall from the right and turn left, then come to the Hanu Brothers Machine
3. Then use the rocket launcher to kill the first monster, then go to the room on the right
4. Then use the first rocket launcher to refresh and break the two walls.
5. Finally, use the rocket launcher to kill three enemies in two places to complete the achievement and receive the reward.
The above is all about how to achieve the full fire achievement in "Honkai Impact: Star Rail". For more game guides, please click the source code website.