I'm thinking about implementing an Achievement system into my 4E campaign, much like the achievements in Xbox 360 games or World of Warcraft. I believe that achievements, while meaning a bit of extra bookkeeping/tracking on my part, will enhance the campaign in a multitude of ways.
Recognition. Extremely heroic or awesome actions will now be rewarded not only with in-game victory, but also out-of-game recognition and celebration.
Permanency. Each achievement will be in the form of a cardstock card or slip, that players will be able to keep with their sheet - tactile reminders of the adventures they've had.
Consolation. Achievements for really bad luck, such as 5 failed saving throws in a row, will (hopefully) lighten the mood and help an unfortunate player get back on his feet.
Humor. Many of the achievements will add humor to the table, either through weird requirements (such as drowning a flying monster) or funny titles referencing running/inside jokes.
Redemption. I haven't figured out how this will work, but players will be able to "cash in" achievement points they have earned for favors in-game. Not like a store, but more like...divine favours, like the gods themselves are rewarding them for their feats. Rerolls would be the simplest exchange, but maybe also things like a permanent bonus to a skill or defense. Minor boons.
Some achievements are easy to plan out - kill X enemies, deal over X damage in a single attack, etc. I've written up plenty of those already. The harder part now is coming up with creative achievements that will suitably reward a player doing something bizarre and unexpected. In other words, exactly what someone should get an achievement for.
Here are some sample achievements I intend to use:
• Kill an enemy with a power that does not deal damage or ongoing damage.
• Kill an enemy with a utility power.
• Roll a natural 20 three times in one encounter.
• Fall 100 feet and survive (only attainable in Heroic tier)
• Knock an enemy off a ledge, cliff, etc., where it dies from fall damage.
• Perform an area attack that includes at least 2 friendly targets where you miss every friendly target but hit every enemy target.
• Have at least 3 players at the table wearing pop boxes on their heads at the same time.
• Miss three attack rolls in a row.
• Go an entire game night without taking any damage.
• Survive an encounter while wearing armor you are not proficient with.
One potential drawback of achievements is people getting carried away with them and "achievement-hunting," but this won't be an issue because the achievement list & requirements will be secret, and each achievement will only be attainable once. So players won't be able to intentionally try for achievements.
Another drawback will be trying to keep track of achievements that are bestowed for things like 100 kills, or like in the list above, surviving an entire night without taking damage. I'm considering making a graph with each character's name on one axis and achievements the character qualifies for on the other axis. That way, I can tally kills or put an X in a character's box when they no longer qualify for an achievement. Not sure how well this will actually work, but it seems a decent method in theory.
I've ran the idea by a few of my players and they were very excited about the idea, so it should be fun to see how they react when the achievements start popping up!