Mouse Playhouse
Mouse Playhouse is a Virtual Reality game using the HTC Vive where players manipulate objects and create pathways through which they guide mice to the end goal: a giant wheel of cheese!
Responsibilities
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Managed and led a team of 18 developers, maintaining the vision for the game with a Game Design Document (GDD)
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Designed the game to be grid based which significantly improved development speed and iteration time
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Created the object snapping system for placing special objects on the table
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Implemented and iterated on the mouse's movement system and special object rules
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Designed and developed the tutorials aimed at on-boarding players even if they had no prior VR experience
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Oversaw playtests focused on gauging the game's difficulty curve with analytics
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This meant moving to a grid based system of gameplay, which allowed for much quicker iteration on the design of levels, and helped programmers write movement rules for the mouse. At this point, the gameplay shifted to be much more puzzle oriented.
Grid Based Gameplay
Early prototypes of Mouse Playhouse had variants where the player could pick up any object and place it arbitrarily on a table. It was very difficult to teach the player rules or mechanics with this much freedom. We decided to put restraints on where the player could place objects, and how the mice moved.
Object Snapping System
While an object is being held, the object checks to see what its closest grid position is by rounding its x, y, and z coordinates to the nearest grid unit size.
Objects also check their grid position when they are about to be placed on the table. Not only do they check their current grid location, they also check positions adjacent to themselves. If everything checks out (meaning this is a valid spot to put this object), a blue clone of the mesh of the object you're holding appears in this grid location. If the object cannot be placed there, its clone turns red.
Mouse Movement
All entities on the table follow a simple movement pattern:
1) Keep moving forward
2) If you hit a wall/edge, turn around
3) If you hit a wedge, change directions
If the object is blue, then it'll snap to that position when you let go of it, and if the object is red it returns to the position from which you picked it up.
Above is our first implementation of the mouse's movement. As we added more objects that interact with the mouse, we kept adding more rules.
Eventually, our final product had a series of special cases all dealing with objects in adjacent spaces to the moving character, as you can see below. When the mouse is ready to make a move, the mouse checks all of the necessary neighboring grid spaces, chooses the next space to travel to, and then starts to move.
On-boarding Tutorials
When designing the introduction and tutorial part of the game, we expected to simply teach the player how to play our game. Well, because the HTC Vive is so new, the majority of our playtesters had never used VR before. We ended up having to make sure our tutorials were simple enough that even if you never touched a Vive before, you could still play our game.
We had to show players where all the buttons were that you needed to press to play our game, and we couldn't assume they were familiar with the Vive setup. This also meant when we were designing the control scheme for the game, we needed to cut down the number of actions that you needed to take.
During proof of concept, we had a lot of the buttons mapped to do different things, like start and stop the mouse, or change modes, size, position, etc. But, in order to make the game as simple as possible we simplified down to only 2 buttons and mirrored those controls for the right and left controllers.
Difficulty Curve
We added functionality to Mouse Playhouse to automatically record data like number of player deaths on each level, or amount of time spent on each level. When the player closes the game, this data is output to a log. Our team was fortunate enough to have a usability producer who was able to analyze this data from our playtests.
With these usability reports, we were able to identify where certain pressure points were in the game. This feedback loop helped to better balance difficulty within the game as the player progressed through each level set.