River Runner Construction Kit 2D

River Runner Construction Kit 2D is a modular gameplay kit for building side-view 2D auto-run and river-platforming courses in Unity.

Assemble a route from seven standardized 8-unit river segment prefabs. Add the included Puffy Orb raft runner, configurable currents, overlapping boost and slowdown zones, moving rafts, hazards, collectibles, checkpoints, and a conditional finish goal.

INCLUDED CONTENT

• 19 prefabs in total
• 7 modular 8-unit course segments
• 12 reusable runtime components
• 3 playable demo scenes: Beginner Stream, Hazard Gauntlet, and Night Rapids
• 1 Parts Gallery scene
• 1 Puffy Orb raft runner prefab created for this asset
• Current and speed zones
• Knockback or checkpoint-respawn hazards
• Elliptical looping obstacles
• Kinematic moving platforms and rafts
• Collectibles, checkpoints, a conditional goal, run timing, and UnityEvent extension points
• Damped 2D camera follow
• English and Japanese Quick Start guides, API reference, asset catalog, compatibility notes, changelog, third-party notices, and generative-AI disclosure

COURSE BUILDER

The included Course Builder is a focused Editor window. It creates or finds an active-scene course root and appends a selected segment at the next 8-unit local +X connection with Undo support. Publisher-only asset generation, demo generation, automated playtest, capture, validation, export, and Build Settings automation are not included.

COMPATIBILITY

Version 1.0.1 is supported and validated with Unity 2022.3 LTS using the Built-in Render Pipeline. It was clean-import tested with Unity 2022.3.22f1. URP and HDRP support are not declared.

The built-in keyboard and mouse controls require Active Input Handling to be set to Input Manager (Old) or Both. In an Input System-only project the package compiles and the built-in polling is disabled. Connect project Input Actions or UI controls to the documented public methods. No ready-made Input System actions or adapter component are included.

No third-party packages are required. The package includes no telemetry, networking, Steam SDK, API keys, audio, music, inventory, persistence, pooling, or fixed scene-transition system.

SCOPE

Movement and current values are tunable arcade examples. This package is not a fluid, water-surface, or buoyancy simulation.

ORIGINAL-GAME PROVENANCE

The reusable kit is an independent Unity 2022.3 implementation inspired by a river-running stage concept from Chihuahua Games' released title LOST IN LOST JAPAN.

The original regional scene, level data, UI, characters, boat, audio, regional references, Steam features, and branding are not included as runtime or reusable toolkit content. The Puffy Orb runner, river pieces, hazards, tokens, props, prefabs, code, and demo scenes are asset-specific content.

One publisher-owned PNG screenshot from LOST IN LOST JAPAN (Steam App ID 4531750) is included under Documentation/OriginalGameReference solely to document provenance. It is not loaded by the runtime, used by the prefabs or demo scenes, or represented as a product feature.

The promotional video contains a short original-game reference segment. That segment is visibly labeled "REFERENCE GAMEPLAY - NOT INCLUDED IN THIS ASSET" before the video transitions to the included asset-kit content.