Replica

Replica is a 2D puzzle platformer made in four days for the 2025 GMTK Game Jam under the theme Loop. I was responsible for designing and programming the entire echo system, which lets players cooperate with past versions of themselves after dying or running out of time. Up to five echoes can exist at once, each repeating the exact sequence of inputs from the previous runs and interacting with the current player.

The first version of the system recorded player positions each frame, but that approach fell apart when the player left the ground. Gravity and vertical movement caused desyncs, so I switched to an input-based recording model that logged every button press and stored it in small JSON files. Each iteration reloaded its own file and replayed inputs through the movement system, keeping the behavior consistent while staying lightweight.

Echoes were designed to collide with the player to create platforms or tools that supported future runs. This led to puzzles that forced players to think ahead using one version to press switches or stack themselves to reach high ledges. I didn’t include fail-safes for paradoxes on purpose; the point was to make players consider how their decisions ripple across timelines. The game stayed stable and efficient, with each recording only a few kilobytes in size.

My priority during the jam was to get the mechanic working smoothly and make it feel intuitive. Even with limited time, Replica became a great study in how player input, and memory systems can work together to create interesting level based puzzles.

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