diff --git a/source/core/assets/images/lava_bg.png b/source/core/assets/images/lava_bg.png
index 869b4c9a0..cca706805 100644
Binary files a/source/core/assets/images/lava_bg.png and b/source/core/assets/images/lava_bg.png differ
diff --git a/source/core/src/main/com/csse3200/game/areas/terrain/TerrainFactory.java b/source/core/src/main/com/csse3200/game/areas/terrain/TerrainFactory.java
index 2567da499..61723330c 100644
--- a/source/core/src/main/com/csse3200/game/areas/terrain/TerrainFactory.java
+++ b/source/core/src/main/com/csse3200/game/areas/terrain/TerrainFactory.java
@@ -23,7 +23,6 @@
 import com.csse3200.game.screens.GameLevelData;
 import com.csse3200.game.services.ResourceService;
 import com.csse3200.game.services.ServiceLocator;
-
 import static com.csse3200.game.screens.MainGameScreen.viewportHeight;
 import static com.csse3200.game.screens.MainGameScreen.viewportWidth;
 
@@ -37,6 +36,7 @@ public class TerrainFactory {
   int selectedLevel = GameLevelData.getSelectedLevel();
   private Texture whiteTexture;
 
+
   /**
    * Create a terrain factory with Orthogonal orientation
    *
@@ -48,7 +48,6 @@ public TerrainFactory(CameraComponent cameraComponent) {
     Viewport viewport = new ScreenViewport(camera);
     viewport.update(viewportWidth, viewportHeight, true);
     stage = new Stage(viewport, new SpriteBatch());
-
     camera.update();
 
     Pixmap pixmap = new Pixmap(1, 1, Pixmap.Format.RGBA8888);
@@ -108,9 +107,19 @@ private TiledMapRenderer createRenderer(TiledMap tiledMap, float tileScale) {
 
   private TiledMap createForestDemoTiles(GridPoint2 tileSize, TextureRegion grass) {
     TiledMap tiledMap = new TiledMap();
+    /**
+     * Creates a background layer for a tiled map with the specified dimensions and tile size.
+     *
+     * @param width The width of the layer in tiles.
+     * @param height The height of the layer in tiles.
+     * @param tileWidth The width of each individual tile in pixels.
+     * @param tileHeight The height of each individual tile in pixels.
+     */
 
-    // Create a background layer
     TiledMapTileLayer backgroundLayer = new TiledMapTileLayer(20, 8, tileSize.x, tileSize.y);
+    /**
+     * Define a TextureRegion to be used as the background texture.
+     */
     TextureRegion backgroundTextureRegion ;
 
     switch (selectedLevel) {
@@ -129,14 +138,30 @@ private TiledMap createForestDemoTiles(GridPoint2 tileSize, TextureRegion grass)
         break;
     }
 
-    // Create a single cell for the entire background image
+    /**
+     * Creates a single cell with the specified background texture region and adds it to the background layer
+     * of a tiled map. The background layer represents the entire background image of the map.
+     *
+     * @param backgroundTextureRegion The TextureRegion to use as the background texture.
+     * @param tileSizeX The width of each individual tile in pixels.
+     * @param tileSizeY The height of each individual tile in pixels.
+     * @param tiledMap The TiledMap to which the background layer should be added.
+     */
     Cell cell = new Cell();
     cell.setTile(new StaticTiledMapTile(backgroundTextureRegion));
     backgroundLayer.setCell(0, 0, cell);
 
     tiledMap.getLayers().add(backgroundLayer);
 
-    // Create a grass layer
+    /**
+     * Creates a grass layer for the tiled map with the specified dimensions and tile size, filling it with
+     * grass tiles using the provided grass terrain tile.
+     *
+     * @param tileSizeX The width of each individual tile in pixels.
+     * @param tileSizeY The height of each individual tile in pixels.
+     * @param grassTile The TerrainTile representing the grass tile to be used for the layer.
+     * @param tiledMap The TiledMap to which the grass layer should be added.
+     */
     TerrainTile grassTile = new TerrainTile(grass);
     TiledMapTileLayer grassLayer = new TiledMapTileLayer(20, 8, tileSize.x, tileSize.y);
     fillTiles(grassLayer, new GridPoint2(20, 8), grassTile);
diff --git a/source/core/src/test/GameLevelDataTest.java b/source/core/src/test/GameLevelDataTest.java
new file mode 100644
index 000000000..c9f6efcd2
--- /dev/null
+++ b/source/core/src/test/GameLevelDataTest.java
@@ -0,0 +1,30 @@
+import com.csse3200.game.screens.GameLevelData;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class GameLevelDataTest {
+
+    @Test
+    void shouldInitializeSelectedLevelToMinusOne() {
+        assertEquals(-1, GameLevelData.getSelectedLevel());
+    }
+
+    @Test
+    void shouldSetSelectedLevel() {
+        GameLevelData.setSelectedLevel(2);
+        assertEquals(2, GameLevelData.getSelectedLevel());
+    }
+
+    @Test
+    void shouldSetSelectedLevelToZero() {
+        GameLevelData.setSelectedLevel(0);
+        assertEquals(0, GameLevelData.getSelectedLevel());
+    }
+
+    @Test
+    void shouldSetSelectedLevelToNegativeValue() {
+        GameLevelData.setSelectedLevel(-5);
+        assertEquals(-5, GameLevelData.getSelectedLevel());
+    }
+}