Phase Swap Demo
ROLE
Solo Demo
Concept
Phase Swap is a third-person puzzle adventure set in a quantum laboratory after a massive explosion destabilizes reality. Certain objects now exist in an unstable state, shifting between ghost-like intangibility and solid physical form. As a survivor altered by the blast, the player gains the ability to swap phases with these objects, using this power to solve spatial puzzles and navigate the facility. Walls and stable structures remain unchanged, forcing players to think strategically about what can and cannot be manipulated. Along the way, the protagonist encounters former colleagues driven insane by the accident, and must rely on phase control rather than violence to restrain enemies and escape the lab.
Design Approach
As a demo designed for an approximately 10-minute gameplay experience, this project intentionally avoids introducing too many complex mechanics. Instead, it focuses entirely on a single core gameplay concept: Phase Swapping between Ghost and Solid states.
Through the rule that ghost and solid states cannot collide with each other, players rely solely on this ability to solve puzzles built around spatial reasoning and collision relationships, and later apply the exact same logic to handle enemies.
The key advantages of this design approach are:
-
Highly focused mechanics — players do not need to learn multiple systems at once, keeping the learning curve accessible.
-
Repeated reinforcement of the core logic — phase swapping is consistently used across puzzles, combat scenarios, and risk management, allowing players to quickly form a stable mental model.
-
Distinctive gameplay experience — the dynamic collision rules challenge traditional spatial intuition, offering a fresh and engaging form of puzzle interaction.
Level Structure
The demo consists of six rooms, clearly divided into three stages.
Stage 1 (Rooms 1–3): Teaching and Mastery
The first stage is designed to introduce the mechanic and build player familiarity:
-
Room 1 introduces the phase swap ability and helps players understand the fundamental rule.
-
Room 2 reinforces the ghost/solid collision relationship in a safe environment.
-
Room 3 serves as the first major test, requiring multiple planned swaps to ensure the player can confidently apply the mechanic to solve problems.
Stage 2 (Rooms 4–5): Introducing Enemies into the Same Rule System
The second stage formally introduces enemies and integrates them into the same phase framework:
-
Room 4 teaches players that enemies also obey the ghost/solid rules — interaction is only possible when both are in the same state. Players can temporarily restrain enemies using phase control, but must release them in order to progress, fully understanding enemy behavior and risk.
-
Room 5 presents a puzzle that requires patience and sustained positioning, forcing players to solve under the pressure of an approaching enemy. This encourages the strategy of controlling enemies first, then solving the puzzle, as a safer and more efficient approach.
Stage 3 (Room 6): Final Integration Challenge
The final room acts as a complete culmination of the demo:
-
It introduces more enemies, a more complex spatial layout, and constant pursuit pressure.
-
Players must combine all previously learned knowledge and skills.
-
Although the difficulty increases significantly, the gradual buildup ensures that players can systematically break down the challenge and ultimately escape the laboratory.
Summary
Overall, the design follows the principle of “one core mechanic, reused across multiple scenarios and systems.” Through a clear learning curve and progressively layered challenges, the demo delivers meaningful gameplay depth within a short experience.
This approach not only keeps the development scope manageable, but also ensures the demo presents a complete, convincing, and polished expression of the game’s central idea.
Technical Work
The entire project was developed using Unreal's Blueprint system without any C++ code. Enemy animations were downloaded from Mixamo—the Not So Scary Zombie Pack.
My primary technical contributions to this project included the following:
Phase Swap System
An Outline Post Process Material for Selection
Enemy using Behaviour Tree with Animation
A Ghost Material
Modified ThirdPersonCharacter to Realize Required Functionalities
