diff --git a/dev-journal.md b/dev-journal.md
index 79abf4f..3169ca4 100644
--- a/dev-journal.md
+++ b/dev-journal.md
@@ -12,7 +12,7 @@
 - Theme: "Cosmic Garden" - a space gardening idle game
 - Built core game engine with click harvesting, buildings, upgrades, achievements
 - Designed 12 buildings across 4 tiers (Star Sprout → Void Fern)
-- Added 15+ upgrades and 20 achievements
+- Added 15+ upgrades and 30 achievements
 - Implemented auto-save, offline progress, export/import
 - Built responsive dark-themed UI
 
@@ -131,3 +131,27 @@
 - Achievement expansion (prestige-related achievements)
 - Mobile touch optimizations
 - Consider adding more visual polish to the click button
+
+---
+
+### Session 6 - 2026-08-20 (Evening)
+**Status:** ✅ Achievement Expansion Added
+
+#### What was done:
+- Added 10 new achievements, bringing total from 20 to 30
+- New prestige achievements: Cosmic Rebirth (first prestige), Stellar Adaptation (5 prestiges), Cosmic Ascension (10 prestiges), Eternal Gardener (100 total essence), Quantum Growth (1,000 total essence)
+- New building milestone achievements: Void Weaver (25 Void Ferns), Supernova Growth (25 Supernova Seeds)
+- New click power achievements: Powerful Harvester (1,000 click power), Divine Touch (10,000 click power)
+- New time-based achievement: Dedicated Gardener (play for 1 hour total)
+- Updated achievement counter in UI from (0/20) to (0/30)
+- Updated Session 1 journal entry to reflect 30 achievements
+
+#### Files modified:
+- `js/achievements.js` - Added 10 new achievement definitions
+- `index.html` - Updated achievement count display
+- `dev-journal.md` - Updated session log and added Session 6 entry
+
+#### Next goals:
+- Mobile touch optimizations (tap feedback, responsive layout)
+- Consider adding more visual polish to the click button
+- Achievement progress tracking in stats panel
diff --git a/index.html b/index.html
index ef6a530..3681677 100644
--- a/index.html
+++ b/index.html
@@ -58,7 +58,7 @@
                 </div>
 
                 <div id="achievements-tab" class="tab-content">
-                    <h3>Achievements (0/20)</h3>
+                    <h3>Achievements (0/30)</h3>
                     <div id="achievements-list"></div>
                 </div>
 
diff --git a/js/achievements.js b/js/achievements.js
index d88279b..48dd06b 100644
--- a/js/achievements.js
+++ b/js/achievements.js
@@ -135,7 +135,7 @@ const ACHIEVEMENTS = {
         icon: '💧',
         condition: (state) => Game.getProductionPerSecond() >= 100
     },
-    
+
     rushingRiver: {
         id: 'rushingRiver',
         name: 'Rushing River',
@@ -143,13 +143,97 @@ const ACHIEVEMENTS = {
         icon: '🌊',
         condition: (state) => Game.getProductionPerSecond() >= 1000
     },
-    
+
     cosmicFlood: {
         id: 'cosmicFlood',
         name: 'Cosmic Flood',
         description: 'Reach 100,000 stardust/sec',
         icon: '🌊',
         condition: (state) => Game.getProductionPerSecond() >= 100000
+    },
+
+    // Prestige achievements
+    firstPrestige: {
+        id: 'firstPrestige',
+        name: 'Cosmic Rebirth',
+        description: 'Prestige for the first time',
+        icon: '🌀',
+        condition: (state) => state.prestigeCount >= 1
+    },
+
+    stellarAdaptation: {
+        id: 'stellarAdaptation',
+        name: 'Stellar Adaptation',
+        description: 'Prestige 5 times',
+        icon: '⭐',
+        condition: (state) => state.prestigeCount >= 5
+    },
+
+    cosmicAscension: {
+        id: 'cosmicAscension',
+        name: 'Cosmic Ascension',
+        description: 'Prestige 10 times',
+        icon: '🌟',
+        condition: (state) => state.prestigeCount >= 10
+    },
+
+    eternalGardener: {
+        id: 'eternalGardener',
+        name: 'Eternal Gardener',
+        description: 'Earn 100 total Stellar Essence',
+        icon: '💎',
+        condition: (state) => state.totalPrestigeEssence >= 100
+    },
+
+    quantumGrowth: {
+        id: 'quantumGrowth',
+        name: 'Quantum Growth',
+        description: 'Earn 1,000 total Stellar Essence',
+        icon: '🔮',
+        condition: (state) => state.totalPrestigeEssence >= 1000
+    },
+
+    // Building milestone achievements
+    voidWeaver: {
+        id: 'voidWeaver',
+        name: 'Void Weaver',
+        description: 'Own 25 Void Ferns',
+        icon: '🌿',
+        condition: (state) => (state.buildings.voidFern || 0) >= 25
+    },
+
+    supernovaGrowth: {
+        id: 'supernovaGrowth',
+        name: 'Supernova Growth',
+        description: 'Own 25 Supernova Seeds',
+        icon: '💥',
+        condition: (state) => (state.buildings.supernovaSeed || 0) >= 25
+    },
+
+    // Click power achievements
+    powerfulHarvester: {
+        id: 'powerfulHarvester',
+        name: 'Powerful Harvester',
+        description: 'Reach 1,000 click power',
+        icon: '✋',
+        condition: (state) => Game.getClickPower() >= 1000
+    },
+
+    divineTouch: {
+        id: 'divineTouch',
+        name: 'Divine Touch',
+        description: 'Reach 10,000 click power',
+        icon: '🤚',
+        condition: (state) => Game.getClickPower() >= 10000
+    },
+
+    // Time-based achievement
+    dedicatedGardener: {
+        id: 'dedicatedGardener',
+        name: 'Dedicated Gardener',
+        description: 'Play for 1 hour total',
+        icon: '⏰',
+        condition: (state) => (Date.now() - state.startTime) >= 3600000
     }
 };