The design process of Mouse Trap add on

Mouse Trap is a procedural content generation add on to one of our existing project built in Unity aimed to enhance the player's open world experience by controlling the intensity of the level.

Role in Mouse Trap: Programmer / Designer

Engine: Unity3D

Team size: Solo
Language: C#

Main contributions to MouseTrap: Stress system / Rapid prototyping

Boss that follows the system

Origins

Mouse Trap was initially an open world boss fighting game that allows the player to explore and take their time to prepare for the boss fight. I decided to implement an AI system which is similar to L4D2's director's AI to control the intensity curve of the level due to the lack of control as to where the player will be exploring at any given time.

This portfolio will cover my contributions and its process in this project.

Stress system

Perceived Stress - Player

This is the focus of this system. The main purpose is to artificially create a score that represents the player's cognitive load depending on their tasks and progression. The factors went through multiple iterations before the final 3 were decided.

Here are the factors that I considered and their reasoning:

Number of times player has been hit in the past 5 seconds
- This factor was chosen as it represents the player's inability to avoid attacks as they are combo'd, which the player could be panicking.
Amount of traps set up
- This factor was chosen to represent how prepared the player is to fighting the boss. More traps set up means the player is more prepared to fight the boss.
Player's current health
- I felt that the player's current health can be a good judge as it can affect the player's judgement in a situation, such as running away instead of fighting the boss.

Perceived Stress - Boss

Apart from the player's Perceived Stress, the boss too has its own Perceived Stress if the player is too powerful. This creates a possibility of a dynamic gameplay where it is affected by the player's skills and playstyle.

Here are the factors considered for the boss

Boss current health
- Just like the player, the boss also gets stressed when they are about to die which causes them to run.
Damage taken while trapped
- There is a possibility of traps lying around and the boss stepping into it without the player nearby. Thus, this helps judge the player's skill level and playstyle as it means the player is skillful if they are able to capitalize on every trap and deal maximum damage.

Decision maker

With the two Perceived Stress calculations, the decision maker decides on the boss' next actions. Each boss action scores are split equally into 3 parts from 0 - 100 which represents the overall stress level. For example, if the overall stress level is low, the boss might perform attacks more frequently. Or if the total stress level is high the boss might decide to leave the area.

A flow chart was made to help with the logic of the script and to ensure that everything is kept consistent.

Check out the flowchart here!

Post Mortem

Project takeaways

Pointers I learnt from this project which I will take note of in future projects.

Target audience

An important thing I learnt in design is that the target audience is very important. It is impossible to design a game for everyone, and if too many compromises were made, it is not going to satisfy anyone.

Initially the perceived stress factors were not designed with a target audience in mind, it was done based on the intended experience and not the target audience.
- This resulted in mixed feedback from playtesting as the exploration portion was intended for casual players and the boss fight ended up being an experience for skilled players due to the boss behavior.

There are quite a few factors that a player has to consider when playing the game. If I were to adjust the exploration portion for skilled players, it might burn the player out from the constant need to focus.

In order to reduce the player's cognitive load, I decided to adjust the boss fight experience to be more casual. This helped remove the sudden change in pace causing a spike in stress levels when the player begins a boss fight, streamlining the experience for a gradual increase in intensity.

Thus, from this I learnt that designing with a target audience in mind helps streamline the intended experience better.