FootballAR is a multiplayer AR game built in Unity & Vuforia.
The player uses a simple drag & release interaction to aim and apply force on the ball in 3D space, trying to score goals against a moving goalkeeper.
The game broadcasts over local WiFi to detect other players and provides a simple lobby system to start matches.
I wrote the gameplay engine in C# (because JS wasn’t quite as cool back then), making heavy use of the rigid body physics in Unity. The hardest part of making a working multiplayer game was syncing physics state across two devices, but over WiFi a crude high-traffic approach worked when using a deterministic physics simulator.