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Role: Level Designer/Quest Designer

Engine: Fallout 4 Creation Kit

Genre: RPG, FPS

Development Time: 150 hours

Development Info and Responsibility


Quest Flowchart


  • Create a unique and memorable experience for the player as a detective;

  • Force the player to make meaningful choices.


  • Draft a unique, suspenseful murder mystery with a twist ending;

  • Build the quest in Creation Kit and use global variables to control the progress of the quest;

  • Write 1000 plus dialogue lines including scenes with suspects, witnesses, and environmental storytelling;

  • Script interesting subquest, including luring a dog with bait and NPC blackmailing the player;

  • Script the trigger to start the quest;

  • Construct level-layout;

  • Add aesthetic details and lighting;

  • Playtest and iterate.


Level Overview


The Devotion of Suspect is a Fallout 4 Mod that takes place in Diamond City. The player is asked to investigate the murder of a resident, Bruno. 



To solve the case, the player needs to act as a real detective:


  • Search and collect evidence;

  • Try to pry information from a witness or involved people; 

  • Cross-reference all information and make his own deductions;

  • Make successful accusation by choosing the right death time of victim, the alibis of the suspects, the motives of suspects.



The quest would feel mechanical if one NPC just runs to the player asking for help. To make this detective quest synergize with the Fallout 4 world, the player can either pick up a case folder on Nick Valentine's desk or read a bounty of this case outside Bruno's house or on Dimond City bounty wall.


Searching the Victim's House


The player would find the following clues in the victim's house. Some of the clues would become a quest marker to give the player a direction while the rest will unlock dialogue options in the future.


There are three quest markers, i.e. three main suspects for the player to investigate. The player can approach them in whichever order he would like to.


Skills of level design and environmental storytelling are applied when designing the scene below. 

  • The coroner is placed so that he would catch the player's eye when first entering this house.

  • A light was placed in the right bottom corner of this screenshot so its light hits the silver locket.

  • Bruno was most close with his ex-wife, so he carried the letter to her with him.

  • The broken spectacles are placed on a light-colored board to stand out.

  • The table and the wine bottles near the table were tilted towards the direction of the trash can, where the Bar flyer was placed.

  • Empty wine bottles and lack of furniture indicate the owner of the house was a poor drunk.


Whenever the player picks up or stumbles upon a clue, a message box pops out to tell the player that he had found something valuable. 


Investigating Rivers Bar


From the conversation with the bartender, it was revealed that bartender had a brawl with Bruno last night. Talking to the singer and customers, the player learns Bartender's motive and alibi. The quest marker updates again to Rivers Manor, where the bartender lives so the player can verify his alibi.

  • The player enters the bar from the middle right of the screenshot below.  He would first see the singer as her red dress stands out in the brown color tone of the bar.

  • When the player first entered the bar, the chatting between the customers starts automatically to draw the player's attention.

  • The spotlight towards the stage stands out of other lights to indicate the importance of singer.


Investigating Ex-Wife


Even though the ex-wife claimed that she had a valid alibi, conversation with her boss and daughter would reveal her alibi was fabricated. 



Any quest without changes in pacing would become dull. Luring a dog with bait would entice the player.

To make a dog that would act naturally seek and acquire an iguana stick requires a custom AI package. 

  • The house of the ex-wife is supposed to deliver a warm, welcome feeling to make the player sympathize with the ex-wife and her daughter. 

  • Toys and child books indicate a child lives here.


Investigating The Landlord


The landlord stated that he was looking after a patient last night. However, the patient told the player that after he took some medicine he fell asleep.

  • The patient was showing gratitude towards the landlord when the player walked in, making the player sympathize with the landlord.

  • The clinic's lighting is bright and white to fit with the tone of a clinic.

  • The receptionist told the player that he was working on the medical records, foreshadowing the use of medical records.

Investigating Rivers Manor


The player investigated where the bartender lived and found his motive. Conversation with his family revealed his alibi fabricated.


Make Accusation


At any stage of the quest, the player would be able to go to the security officer in the security office and tell him that the player knew what happened. The security officer gathered all suspects, then the player needs to choose which suspects to accuse, the motive of each suspect, the alibi of each suspect. If the player made any mistake here, the accused suspect would start a combat against the player, forcing the player to kill him, eventually resulting in the quest to fail.

- Timeline of the night when the murder happened -

Timeline with evidence.PNG

All three suspects tried to kill the victim in a sequence, even though the player may accuse one of them or all of  Below is a timeline showing any of the suspects or accuse all of them. There were three suspects in total. The player can accuse them happened at what time, and where. However, the only truth is player can find information or evidence to support it.


00:04 Ask the coroner about the cause of death of the victim;

00:27 Investigate the crime scene

00:39 Getting information from the witness

00:49 Get the alibi of each suspect

02:09 Find out the motive of each suspect

03:05 Cross-reference evidence

03:30 Point out the right death time of the victim

03:48 Point out the right alibi of each suspect

04:13 Choose the right motive for each suspect

04:40 Recount what happened at the crime scene


Quest In An Open World



Give Player Freedom


Even though the player is playing the Sole Survivor in the Fallout 4 world, the player is playing himself. Thus, it is important to give the player choices and freedom.


  • Stand in the shoes of player: one of Fallout 4's acknowledged flaw is that it gives player four dialogue options: yes, no, wait and sarcastic, not providing any methods to fulfill his curiosity. In The Devotion of Suspect, more than four choices for dialogue are given to the player based on the specific situation. For example, when the player is questioning a suspect, he can ask about the suspect's alibi, his relationship with the victim, his knowledge about evidence, etc. 

Non-Linear Quest Design

There are two methods to design a quest non-linearly.

  • The first one is that player can complete task A, B, C in any order then trigger the next stage of the quest. In The Devotion of Suspect, the player can investigate the suspects or collect evidence in any order.

non-linear quest design.PNG


  • The second one is that the player can determine if he wants to proceed with the quest according to his progress. However, there are different endings based on when he made the choice. For example, in The Devotion of Suspect, the player can decide when to accuse the suspect. However, the player must make choices about the suspects' motive, alibi, and evidence during the prosecution. Therefore, if the player decided to rush before acquiring enough information, he might make the wrong accusation, or would fail the prosecution. 


non-linear quest design_2.PNG

Tell a Story Right 


Many methods are used in The Devotion of Suspect to make sure the player gets the story.

  • Unfold from another perspective: rather than having everything shown directly to the player, have another person talk about it or give player terminal log to read does a more subtle telling of a story. In The Devotion of Suspect, player talks to the friends and colleagues of suspects to know them.

  • The principle of sufficient reason: the pretext of the quest should be a reasonable result of multiple elements: the background of the game, the history of where the quest happened and the personality of NPCs. Even though these factors are not necessarily revealed at the beginning of the quest, they should still make the quest reasonable. 

  • Environment Story Telling: adding details to the level constructions that explains what has happened. In The Devotion of Suspect, every NPCs residents are populated to bring out the background of the residents. For example, the victim's house is littered with wine bottles as he is an alcoholic. 


What Went Well

  • The quest is reasonable: the victim's reason of death, the motives of the suspects, the alibis of the suspects and other elements in this detective level are valid. The player would be able to make correct deductions if he has collected enough information.

  • I was able to deliver a quest that the endings of the quest are totally based on the player's knowledge and effort into the quest.


  • There were 1000 lines of dialogue, 23 scenes, and 20 NPCs in total. Several scenes include complex dialogue choices linking to different scene phases. In other words, the workload was huge and challenging. I was able to complete the level in 150 hours by planning before construction: in the early stage of development, I created charts and tables to organize the scenes, the relationships between NPCs, and how the alibis worked, etc.

What I Learned

  • Instead of using the quest stage, a global variable is a good way to control the progress of a quest.

  • Lighting creates a significant impact on the atmosphere. 

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