Achievements have spread like wildfire in the world of gaming and are quite apparently here to stay. Me, I usually don’t like them at all since most of them are either trivial to get (You have found the jump button, achievement!) or require you to jump through hoops for no purpose other than to get the achievement (Slay 15 turkeys in 3 minutes.) Blizzard’s upcoming Starcraft 2 on the other hand contains a number of really well done achievements. The key seems to be to reward players for doing the right thing.
One of the new Starcraft 2 achievements, for example, is earned by canceling a building that is under attack by an opponent. Doing so will return a part of the resources invested into the building, making it a good choice once you realize that you won’t be able to save your building from your opponent’s forces anyway. If you are a somewhat experienced player you will get this achievement naturally while playing. It won’t be a big deal but you will feel reinforced in your style of play and know that you did something right. If you are a new player though you might not know that canceling is something you should be doing. But when you check the list of achievements available to you, you might see this one and might be guided into improving your gameplay through it.
Blizzard has really taken this guiding functionality of achievements to heart with Starcraft 2, going so far as to actually include achievement groups called guides that are designed to lead you slowly into competitive play instead of just throwing you into cool water. Play some practice games against the computer with each race and get achievements for that. Then maybe you should go on and play some placement matches against real players to determine the level at which you should play and so on.
I also quite like achievements that reward you for doing something cool, such as killing a lot of units in very little time or dodging a missile. These are good plays that happen naturally in games but again make you feel as if you are playing well. In contrast to the ones above, these aren’t really intended to teach players the game. You don’t go out intending to kill a lot of units in one stroke, it’s just a result of good placement and unit composition.
A problem arises when there are achievements that look like one of the types above, but really are more of the jump-through-hoops type. An example would be the Yamato Master Blaster achievement from Starcraft 2. It requires you to shoot 20 units with a low-usage-frequency ability of a high end unit that is always never seen in a serious game. Getting far enough in a game to complete this achievement is more a sign of bad play than good play, teaching exactly the wrong things. World of Warcraft has lots of these types of achievements as well. Loatheb in Naxxramas for example has an inherent mechanic that increases player damage. This is counterbalanced by the boss having an insane amount of health. The achievement is to kill the boss without using the extra damage which isn’t really harder, it just takes ages.
If these kinds of achievements were merely annoying I wouldn’t care much since I could just ignore them, but they take away part of the teaching functionality that the other above-mentioned achievements have. I think one could put a lot more effort into the good types and leave the bad ones out altogether.