Inspiration
I wanted the hands themselves to be the game. The idea: Migi from Parasyte meets a Tamagotchi. A small creature that grows out of your own real hand. My girlfriend also broke her Achilles tendon, so if I wanted her to test the game, it had to be playable seated without any adjustment.
What it does
ParaKo is a short mixed-reality story played only with your hands, seated, in passthrough. A strange plant takes root in your left hand: a moss hand grows over your real one, and a one-eyed creature opens in your palm.
- Thumb microgestures move it between your palm and fingertips
- Sway your hand to catch flies, and pinch to make it bite
- Feeding it grows gifts that change what your hands can do: a claw that snaps with your pinch, then a tiny hand that copies your fingers
- Your other palm holds a little world, and turning your hand over steps you into a place
No controllers, no fail states, no text tutorials: ghost hands show each gesture. It's a small story about caring for something that was never made for this world.
How we built it
Unity 6 (URP), OpenXR and the Meta XR SDK (Core + Interaction SDK) on Quest 3/3S.
- Hand input: one input layer turns the tracked hands into joints, pinch strength, hand openness and microgestures. All gameplay logic sits on top in plain C#, covered by unit tests.
- The moss hand: a mesh skinned to the 26 tracked joints that fully covers your real hand. Meta's hand meshes render depth-only, so your other hand and forearm hide virtual parts correctly.
- The creature: pinch strength drives its jaw and claw, your hand openness makes it retract and sleep, and its eye follows you and the flies.
- Places: each place is a small diorama on a virtual table, plus a colour grade on the passthrough, with spatial audio.
- Tutorials: real hand poses recorded in the headset and replayed as ghost hands.
Developed with Claude Code in Rider as an AI pair programmer: I designed and directed the game and tested every change in the headset; Claude wrote the C# and editor tooling and built the 3D assets in Blender, with me directing the art.
Challenges we ran into
- Making it feel attached. Even a few milliseconds of lag makes the creature float instead of living on your hand. We turned on Fast Motion Mode, read the hand pose one last time right before rendering, and lowered the render scale, because dropped frames read as hand lag.
- Making the creature feel alive. Its stalk is built from springs so it sways and overshoots, its eye looks at you and follows flies, it reacts to many gestures.
- Five gestures, six positions. Microgestures are discrete events, not analog. The palm became a hub: from the palm, each swipe or tap jumps straight to one finger, and from a finger you step to the next.
- Hiding a real hand. Parts stuck onto the passthrough hand never looked attached, so we cover it with a full moss hand instead. Getting clean occlusion at the wrist and forearm took many rounds.
- Seated comfort. Everything has to work within arm's reach, without standing or leaning.
Accomplishments that we're proud of
A creature that feels alive without saying a word. Making the player really feel something at the end of the experience.
What we learned
In mixed reality, low latency and good occlusion matter more than detail. A ghost hand teaches a gesture better than any text.
What's next for ParaKo
Release on the Meta Horizon Store, with more places to visit and more finger tip interactions for your creature.
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