WoW players who were in the game prior to the launch of The Burning Crusade will no doubt remember the patch leading up to the expansion's release, which introduced many of the game system elements that would come to define the post-Crusade game. Blizzard appears to be following that precedent with patch 3.0.2., which hit the test server today. The patch notes posted on WoW's official site enumerate many of the incoming changes to the game in the forthcoming update, all of which will be open to players regardless of whether they purchase the Wrath of the Lich King expansion when it ships in November.
Among the biggest of additions coming in patch 3.0.2 is the Player Achievement system. Similar to the system employed by Xbox Live, WoW's achievements will provide players with a measure of how much of the game they've experienced. Players will earn distinct achievements for all manner of in-game activities. Some examples include advancing their characters to a specific level, winning a specific number of consecutive Arena matches, or completing a specific number of quests. According to Blizzard, the Player Achievement system will launch with over 500 individual achievements.
The system will also launch with a special category of achievements called "Feats of Strength," which will be awarded retroactively for accomplishments performed prior to the launch of Wrath of the Lich King. On the Player Achievement preview page on WoW's official site, Blizzard states that players will "find [Feats of Strength] very difficult -- if not impossible -- to earn," due to some of the circumstances required for unlocking them no longer being possible in the current state of the game.
As an example, a Feat of Strength associated with achieving a certain high rank in the classic honor system is mentioned. Other Feats of Strength could involve clearing pre-expansion raid instances, acquire rare mounts, or achieving a certain reputation level with an old-world faction. Since they're by nature prohibitively difficult for newer players to earn, Feats of Strength will not contribute toward a player's overall achievement point score.

The Player Achievement system will have a dedicated place in the game's UI.
Username
Password

