diff --git a/achievements.admin.inc b/achievements.admin.inc
index 1247ccc749dc24dfaae4a482564e06e5d492385b..263417b7d944669f1363ce75ccd5535d99cdd5ae 100644
--- a/achievements.admin.inc
+++ b/achievements.admin.inc
@@ -70,7 +70,7 @@ function achievements_settings() {
  * Submit callback; clear achievement info cache.
  */
 function achievements_clear_info_cache_submit() {
-  achievements_load(NULL, TRUE);
+  achievements_load(NULL, FALSE, TRUE);
   drupal_set_message(t('Achievements information cache cleared.'));
 }
 
diff --git a/achievements.api.php b/achievements.api.php
index 84d44791c169e574beca118c23e14b069651dd4a..a10b6e1249d4226c47391369483eef82303df6a8 100644
--- a/achievements.api.php
+++ b/achievements.api.php
@@ -45,7 +45,7 @@
  *   - hidden: (optional) The achievement is a sekrit until it is unlocked.
  */
 function hook_achievements_info() {
-  return array(
+  $achievements = array(
     'comment-count-50' => array(
       'title'       => t('Posted 50 comments!'),
       'description' => t("We no longer think you're a spam bot. Maybe."),
@@ -58,7 +58,7 @@ function hook_achievements_info() {
       'storage'     => 'comment-count',
       'points'      => 100,
       'images' => array(
-        'unlocked'  => '/sites/default/files/example.png',
+        'unlocked'  => '/sites/default/files/example1.png',
         // 'hidden' and 'locked' will use the defaults.
       ),
     ),
@@ -74,6 +74,8 @@ function hook_achievements_info() {
       ),
     ),
   );
+
+  return $achievements;
 }
 
 /**
diff --git a/achievements.module b/achievements.module
index f4fd16e6714252423c5e256837b56f8d97f848e5..f9ce394e033bd975f3615212755df18e8e0dd7f8 100644
--- a/achievements.module
+++ b/achievements.module
@@ -146,35 +146,61 @@ function achievements_block_view($delta = '') {
  *
  * @param $achievement_id
  *   The (optional) achievement this request applies against.
+ * @param $grouped
+ *   Whether to return the achievements list flattened (FALSE, the default)
+ *   or grouped into achievement-defined categories. If TRUE, but there is no
+ *   group specified for an achievement, it'll be stored in a "__NONE__" group
+ *   intended to simplify display code. Not compatible with $achievement_id.
  * @param $reset
  *   Forces a refresh of the cached achievement data.
  *
  * @return $achievements
  *   An array of all achievements, or just the one passed.
  */
-function achievements_load($achievement_id = NULL, $reset = FALSE) {
+function achievements_load($achievement_id = NULL, $grouped = FALSE, $reset = FALSE) {
   $achievements = &drupal_static(__FUNCTION__);
 
   if (!isset($achievements) || $reset) {
-    if (!$reset && $cache = cache_get('achievement_info')) {
+    if (!$reset && $cache = cache_get('achievements_info')) {
       $achievements = $cache->data;
     }
     else {
-      $achievements = module_invoke_all('achievements_info');
-
-      // loop through 'em all and set some defaults.
-      foreach ($achievements as $id => $achievement) {
-        $achievements[$id]['id'] = $id; // shorthand.
+      $result = module_invoke_all('achievements_info');
+
+      // determine if we're looking at an achievement or group and create our
+      // master $achievements array. we store the achievements in two separate
+      // forms: one with a tree (for display purposes) and one flattened (for
+      // lookup purposes). the flattened index is referenced so that we save
+      // space in the final serialized blob that cache_set() sends.
+      foreach ($result as $key => $value) {
+        if (isset($value['achievements']) && is_array($value['achievements'])) {
+          $achievements['grouped'][$key] = $value; // copy the whole shebang into realz.
+          foreach ($achievements['grouped'][$key]['achievements'] as $id => $achievement) {
+            $achievement[$id]['id']           = $id;
+            $achievement[$id]['group_id']     = $key;
+            $achievement[$id]['group_title']  = $value['title'];
+            $achievements['flat'][$id] = &$achievements['grouped'][$key]['achievements'][$id];
+          }
+        }
+        else {
+          $value['id']              = $key;
+          $value['group_id']        = '__NONE__';
+          $value['group_title']     = NULL; // moo.
+          $achievements['grouped']['__NONE__']['achievements'][$key] = $value;
+          $achievements['flat'][$key] = &$achievements['grouped']['__NONE__']['achievements'][$key];
+        }
       }
 
-      // no magically-useful way to say "on file change". le sigh.
-      cache_set('achievement_info', $achievements, 'cache', CACHE_TEMPORARY);
+      cache_set('achievements_info', $achievements, 'cache', CACHE_TEMPORARY);
     }
   }
 
-  return $achievement_id
-    ? (isset($achievements[$achievement_id]) ? $achievements[$achievement_id] : FALSE)
-    : $achievements; // return FALSE to stop bum URLs (via the menu %loader callback).
+  if ($achievement_id) { // all my majesty and brilliance, and you just want one result? /me weeps.
+    return isset($achievements['flat'][$achievement_id]) ? $achievements['flat'][$achievement_id] : FALSE;
+  }
+
+  // return the whole shebang in groups or a flattened lookup bucket.
+  return $grouped ? $achievements['grouped'] : $achievements['flat'];
 }
 
 /**
@@ -259,7 +285,7 @@ function achievements_unlocked($achievement_id, $uid = NULL) {
   // grab information about the achievement.
   $achievement = achievements_load($achievement_id);
   if (!isset($achievement)) { // hrm... try a cache refresh?
-    $achievement = achievements_load($achievement_id, TRUE);
+    $achievement = achievements_load($achievement_id, FALSE, TRUE);
   }
 
   if (isset($achievement) && !achievements_unlocked_already($achievement_id, $uid)) {
diff --git a/achievements.pages.inc b/achievements.pages.inc
index 474f4ea01ebddb4230cf33d6c974ce4a8e8bcee3..4b3f91f8df33f1bfc2d9bc98383ab3107ae3e2cc 100644
--- a/achievements.pages.inc
+++ b/achievements.pages.inc
@@ -138,7 +138,7 @@ function achievements_user_page($account) {
   drupal_add_css(drupal_get_path('module', 'achievements') . '/achievements.css');
   drupal_set_title(t('Achievements for @name', array('@name' => $account->name)));
 
-  $achievements = achievements_load();
+  $achievements = achievements_load(NULL, TRUE);
   $unlocks = db_select('achievement_unlocks', 'au')->fields('au', array('achievement_id', 'rank', 'timestamp'))
     ->condition('uid', $account->uid)->orderBy('timestamp', 'DESC')->execute()->fetchAllAssoc('achievement_id');
 
@@ -152,23 +152,18 @@ function achievements_user_page($account) {
       '@total_count'    => count($achievements))),
     '#suffix' => '</div>',
   );
-  foreach ($unlocks as $achievement_id => $unlock) {
-    $build['achievements']['unlocks'][$achievement_id] = array(
-      '#theme'        => 'achievement',
-      '#achievement'  => $achievements[$achievement_id],
-      '#unlock'       => (array) $unlock,
-    );
 
-    // don't show it again in locked loop.
-    unset($achievements[$achievement_id]);
-  }
+  foreach ($achievements as $group_id => $group) {
+    foreach ($group['achievements'] as $achievement_id => $achievement) {
+      $build['achievements'][$group_id][$achievement_id]['#theme'] = 'achievement';
+      $build['achievements'][$group_id][$achievement_id]['#achievement'] = $achievement;
 
-  // display all the remaining locked achievements.
-  foreach ($achievements as $achievement_id => $achievement) {
-    $build['achievements']['locks'][$achievement_id] = array(
-      '#theme'        => 'achievement',
-      '#achievement'  => $achievement,
-    );
+      if (isset($unlocks[$achievement_id])) {
+        $build['achievements'][$group_id][$achievement_id]['#unlock'] = (array) $unlocks[$achievement_id];
+        $build['achievements'][$group_id][$achievement_id]['#weight'] = -$unlocks[$achievement_id]->timestamp;
+        // by setting the weight to the timestamp, the latest unlocks are always shown at the top.
+      }
+    }
   }
 
   return $build;