Add new PNG images for clean and preview outputs

- Added `image_clean.png` to the output directory for the clean image representation.
- Added `image_clean_preview.png` for the preview of the clean image.
- Introduced `image_svg_clean.png` for the SVG clean image representation.

README.md

@@ -8,6 +8,7 @@ Mice! is a strategic game where players must kill rats with bombs before they re
 ## Features
 
 - **Maze Generation**: Randomly generated mazes using Depth First Search (DFS) algorithm.
+- **Original Level Support**: Loads the original `level.dat` from `assets/Rat/level.dat` when present and falls back to `maze.json` otherwise.
 - **Units**: Different types of units such as rats, bombs, and points with specific behaviors.
 - **Graphics**: Custom graphics for maze tiles, units, and effects.
 - **Sound Effects**: Audio feedback for various game events.
@@ -72,6 +73,7 @@ The Mice! game engine is built on a modular architecture designed for flexibilit
 - **Map Class**: Manages the game world structure
 - **Features**:
   - Maze data loading and parsing
+  - DAT archive parsing for the original 32 built-in RATS levels
   - Collision detection system
   - Tile-based world representation
   - Pathfinding support for AI units
@@ -238,6 +240,20 @@ Units interact through a centralized collision and event system:
 - **Libraries**: 
     - `numpy` 2.3.4 for vectorized collision detection
     - `sdl2` for graphics and window management
+
+## Level Sources
+
+- Preferred source: `assets/Rat/level.dat`
+- Fallback source: `maze.json`
+- Current behavior: the loader can read any level from the DAT archive via `--level N`, while still falling back to `maze.json` when the DAT is unavailable.
+- Tile semantics are now preserved internally from the original format: `0=EMPTY`, `1=WALL`, `2=TUNNEL`.
+- Rendering uses those semantics directly: walls use themed grass/flower tiles, tunnel cells use themed cave tiles, and empty cells remain the generic walkable tunnel floor used by the Python version.
+
+### Run examples
+
+- `python rats.py`
+- `python rats.py --level 7`
+- `python rats.py --map maze.json`
     - `Pillow` for image processing
     - `uuid` for unique unit identification
     - `subprocess` for playing sound effects