Single-player 2D exploration and combat prototype using Arcade + Pymunk, ECS via esper, and a Proc system.

• Python: 3.12+
• Engine: Arcade 3.x, Pymunk
• ECS: esper
• Data: Pydantic v2
• RNG: numpy PCG64 (seeded)

Use uv (recommended):

# From repo root
uv venv ; uv sync
uv run crystal-arena

Or with Python:

python -m venv .venv ; .\.venv\Scripts\Activate.ps1
pip install -e ./crystal_arena[dev]
python -m crystal_arena

uv run pytest -q

• src/crystal_arena: core package
• assets: textures, sounds, fonts
• configs: JSON/TOML for items/procs/loot
• tests: unit/property/integration/E2E

This is a minimal arena: a player, one enemy, proc logging, and a debug overlay. Expand systems incrementally.