diff --git a/src/components/CustomGameModal.vue b/src/components/CustomGameModal.vue
index 43ad9f7..9c0fa39 100644
--- a/src/components/CustomGameModal.vue
+++ b/src/components/CustomGameModal.vue
@@ -1,5 +1,5 @@
 <script setup>
-import { ref } from 'vue';
+import { ref, computed } from 'vue';
 import { usePuzzleStore } from '@/stores/puzzle';
 import { useI18n } from '@/composables/useI18n';
 
@@ -8,6 +8,7 @@ const store = usePuzzleStore();
 const { t } = useI18n();
 
 const customSize = ref(10);
+const fillRate = ref(50);
 const errorMsg = ref('');
 
 const snapToStep = (value, step) => {
@@ -19,6 +20,26 @@ const handleSnap = () => {
   customSize.value = snapToStep(Number(customSize.value), 5);
 };
 
+const difficultyLevel = computed(() => {
+  const rate = fillRate.value;
+  const dist = Math.abs(rate - 50);
+  
+  if (dist <= 5) return 'extreme';
+  if (dist <= 15) return 'hardest';
+  if (dist <= 25) return 'harder';
+  return 'easy';
+});
+
+const difficultyColor = computed(() => {
+  switch(difficultyLevel.value) {
+    case 'extreme': return '#ff3333';
+    case 'hardest': return '#ff9933';
+    case 'harder': return '#ffff33';
+    case 'easy': return '#33ff33';
+    default: return '#33ff33';
+  }
+});
+
 const confirm = () => {
   const size = parseInt(customSize.value);
   if (isNaN(size) || size < 5 || size > 80) {
@@ -26,7 +47,7 @@ const confirm = () => {
     return;
   }
   
-  store.initCustomGame(size);
+  store.initCustomGame(size, fillRate.value / 100);
   emit('close');
 };
 </script>
@@ -52,6 +73,29 @@ const confirm = () => {
           <span>80</span>
         </div>
       </div>
+
+      <p>{{ t('custom.fillRate') }}</p>
+      <div class="input-group">
+        <div class="range-value">{{ fillRate }}%</div>
+        <input 
+          type="range" 
+          v-model="fillRate" 
+          min="10" 
+          max="90"
+          step="5"
+        />
+        <div class="range-scale">
+          <span>10%</span>
+          <span>90%</span>
+        </div>
+      </div>
+
+      <div class="difficulty-indicator">
+        <span class="label">{{ t('custom.difficulty') }}:</span>
+        <span class="value" :style="{ color: difficultyColor }">
+          {{ t(`difficulty.${difficultyLevel}`) }}
+        </span>
+      </div>
       
       <p v-if="errorMsg" class="error">{{ errorMsg }}</p>
 
@@ -87,6 +131,7 @@ const confirm = () => {
   border: 1px solid var(--accent-cyan);
   box-shadow: 0 0 50px rgba(0, 242, 255, 0.2);
   animation: slideUp 0.3s ease;
+  transition: all 0.3s ease-in-out;
 }
 
 h2 {
@@ -161,6 +206,26 @@ input[type="range"]::-moz-range-thumb {
     font-size: 0.85rem;
 }
 
+.difficulty-indicator {
+    margin: 20px 0;
+    font-size: 1.2rem;
+    display: flex;
+    justify-content: center;
+    gap: 10px;
+    align-items: center;
+}
+
+.difficulty-indicator .label {
+    color: var(--text-color);
+}
+
+.difficulty-indicator .value {
+    font-weight: bold;
+    text-transform: uppercase;
+    text-shadow: 0 0 10px currentColor;
+    transition: color 0.3s ease;
+}
+
 .error {
     color: #ff4d4d;
     font-size: 0.9rem;
diff --git a/src/composables/useI18n.js b/src/composables/useI18n.js
index 1ec7a12..3216ac7 100644
--- a/src/composables/useI18n.js
+++ b/src/composables/useI18n.js
@@ -29,6 +29,12 @@ const messages = {
     'custom.cancel': 'Anuluj',
     'custom.start': 'Start',
     'custom.sizeError': 'Rozmiar musi być między 5 a 80!',
+    'custom.fillRate': 'Wypełnienie',
+    'custom.difficulty': 'Poziom trudności',
+    'difficulty.easy': 'Łatwy',
+    'difficulty.harder': 'Trudniejszy',
+    'difficulty.hardest': 'Najtrudniejszy',
+    'difficulty.extreme': 'Ekstremalny',
     'win.title': 'GRATULACJE!',
     'win.message': 'Rozwiązałeś zagadkę!',
     'win.time': 'Czas:',
@@ -128,6 +134,12 @@ const messages = {
     'custom.cancel': 'Cancel',
     'custom.start': 'Start',
     'custom.sizeError': 'Size must be between 5 and 80!',
+    'custom.fillRate': 'Fill Rate',
+    'custom.difficulty': 'Difficulty',
+    'difficulty.easy': 'Easy',
+    'difficulty.harder': 'Harder',
+    'difficulty.hardest': 'Hardest',
+    'difficulty.extreme': 'Extreme',
     'win.title': 'CONGRATULATIONS!',
     'win.message': 'You solved the puzzle!',
     'win.time': 'Time:',
diff --git a/src/stores/puzzle.js b/src/stores/puzzle.js
index e9b343c..c81400b 100644
--- a/src/stores/puzzle.js
+++ b/src/stores/puzzle.js
@@ -120,15 +120,16 @@ export const usePuzzleStore = defineStore('puzzle', () => {
     hasUsedGuide.value = false;
     elapsedTime.value = 0;
     startTimer();
+    saveState();
   }
 
-  function initCustomGame(customSize) {
+  function initCustomGame(customSize, density = 0.5) {
     stopTimer();
     currentLevelId.value = 'custom';
     size.value = customSize;
     
     // Generate random grid
-    solution.value = generateRandomGrid(customSize);
+    solution.value = generateRandomGrid(customSize, density);
     
     resetGrid();
     isGameWon.value = false;
@@ -275,44 +276,9 @@ export const usePuzzleStore = defineStore('puzzle', () => {
     return false;
   }
   
-  function initGame(levelId = 'easy') {
-    // If init called without args and we have save, load it?
-    // User might want to start fresh if clicking buttons.
-    // Let's add explicit 'continue' logic or just auto-load on first run.
-    // For now, let's just stick to explicit init, but maybe load on mount if exists?
-    // The user didn't explicitly ask for "Continue", but "features from HTML".
-    // HTML usually auto-saves and loads.
-    
-    stopTimer();
-    currentLevelId.value = levelId;
-    
-    let puzzle = PUZZLES[levelId];
-    if (!puzzle) {
-        puzzle = PUZZLES['easy'];
-    }
-
-    size.value = puzzle.size;
-    solution.value = puzzle.grid;
-    
-    resetGrid();
-    isGameWon.value = false;
-    elapsedTime.value = 0;
-    startTimer();
-    saveState();
-  }
+  // Duplicate initGame removed
   
-  // Modify initCustomGame similarly
-  function initCustomGame(customSize) {
-    stopTimer();
-    currentLevelId.value = 'custom';
-    size.value = customSize;
-    solution.value = generateRandomGrid(customSize);
-    resetGrid();
-    isGameWon.value = false;
-    elapsedTime.value = 0;
-    startTimer();
-    saveState();
-  }
+  // Duplicate initCustomGame removed
 
   // Duplicate toggleCell/setCell removed
 
diff --git a/src/utils/puzzleUtils.js b/src/utils/puzzleUtils.js
index 3566e5d..fc58dbc 100644
--- a/src/utils/puzzleUtils.js
+++ b/src/utils/puzzleUtils.js
@@ -40,13 +40,12 @@ export function calculateHints(grid) {
     return { rowHints, colHints };
 }
 
-export function generateRandomGrid(size) {
+export function generateRandomGrid(size, density = 0.5) {
     const grid = [];
     for (let i = 0; i < size; i++) {
         const row = [];
         for (let j = 0; j < size; j++) {
-            // ~25% empty cells
-            row.push(Math.random() > 0.25 ? 1 : 0);
+            row.push(Math.random() < density ? 1 : 0);
         }
         grid.push(row);
     }