# Synthesis — Development Progress

> **Last updated:** 2026-02-12  
> **Current phase:** Phase 1 ✅ → Ready for Phase 2

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## Completed

### Phase 0: Project Setup ✅
- [x] Game Design Document (`synthesis-gdd.md`)
- [x] Engine analysis and tech stack selection (`engine-analysis.md`)
- [x] npm project + dependencies (Phaser 3, bitECS, TypeScript, Vite, Vitest)
- [x] TypeScript strict config
- [x] Vite config (HMR, chunk splitting)
- [x] Phaser config (1280x720, pixel-art, arcade physics, top-down)
- [x] BootScene with title screen
- [x] Cursor rules (6 rules: project context, agent workflow, ECS, chemistry, Phaser, data)
- [x] Implementation plan (`IMPLEMENTATION-PLAN.md`)
- [x] Progress tracking (this file)

### Phase 1: Chemistry Engine ✅
- [x] 1.1 Types and interfaces (`src/chemistry/types.ts`)
- [x] 1.2 Element data — 20 real elements (`src/data/elements.json`)
- [x] 1.3 Element registry with lookup by symbol/number (`src/chemistry/elements.ts`)
- [x] 1.4 Reaction engine — O(1) lookup, condition checking, failure reasons (`src/chemistry/engine.ts`)
- [x] 1.5 Reaction data — 34 real reactions (`src/data/reactions.json`)
- [x] 1.6 Compound data — 25 compounds with game effects (`src/data/compounds.json`)
- [x] 1.7 Unit tests — 35 passing (`tests/chemistry.test.ts`)

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## In Progress

_None — ready to begin Phase 2_

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## Up Next: Phase 2 — ECS Foundation

- [ ] 2.1 World setup (bitECS world + time tracking)
- [ ] 2.2 Core components (Position, Velocity, SpriteRef, Health)
- [ ] 2.3 Movement system
- [ ] 2.4 Phaser ↔ bitECS sync bridge
- [ ] 2.5 Entity factory
- [ ] 2.6 Health/damage system
- [ ] 2.7 Visual test (entities moving on screen)

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## Blockers

None

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## Session Log

| # | Date | Phase | Summary |
|---|------|-------|---------|
| 1 | 2026-02-12 | Phase 0 | Project setup: GDD, engine analysis, npm init, Phaser config, BootScene, cursor rules, plan |
| 2 | 2026-02-12 | Phase 1 | Chemistry engine: 20 elements, 25 compounds, 34 reactions, engine with O(1) lookup + educational failures, 35 tests passing |