Genesis (the Microsoft kind): In the beginning, an underpaid team of nerdy Microsoft employees said, "Let there be Achievements," and it was good. Great actually, as no one involved in the creation of the Gamerscore system ever imagined it would turn into such an undeniable phenomenon. If you're reading this, it's likely that you too have succumbed to the siren call, and probably have at least one game on your Gamercard that you played just because you heard it had easy Achievements.
Infinity Ward's Community Relations Manager, Robert Bowling, aptly describes Achievements as a "fantastic way to get your players even more involved in your game and add to the replay value even further. It encourages players to delve deeper into aspects of the game that they may have missed or didn't experience their first time through. The Achievements of a game really shape the playing habits of gamers of all types, where it may encourage a casual player to play again or play through originally on a harder difficulty than they normally would."
The end is the end
Looking back at the Achievements that have come before, it's easy to see what went right, and what went horribly, horribly wrong. The different types of Achievements can be generally consolidated into one of several categories, the first and most common being the Progression Achievement. This type of Achievement was made famous by King Kong, a game that rewarded you the complete 1000 Gamerscore simply for completing the game. The word "simply" being used somewhat loosely, as actually making it to the end credits in King Kong was something of a chore. But therein lay the genius of the system; while it is true that early adopters of the 360 had little else to play (as opposed to the massive wealth of games available today), there is undoubtedly many a gamer who has soldiered on longer than they would with any average last-gen title simply to complete the Achievements.
The system has evolved a bit since the early days, but this type of Achievement, which rewards you for simply progressing through the game as you normally would have, is very much alive and kicking, albeit usually combined with an assortment of other Achievements for a bit of variety. And why not include these Achievements? The tasks you will complete in the main storyline are most certainly going to be far more impactful than finding a few dozen hidden trinkets, so it makes sense that you should be rewarded for saving your village or rescuing the princess. Certainly anyone who finished King Kong felt they had endured quite a bit.
An alternative to incrementally awarding Achievements as the player moves from level to level in the main game is a "Final Boss" Achievement. This is usually preceded by a super-easy "Complete the Tutorial" Achievement, which is akin to Buddhists handing out cheap flowers at the airport before asking for a hefty donation. The idea behind being that once you have already received something, it will be harder to say no in return. So once they've hooked you with the tutorial Achievement, you might just be more likely to stick it out until the end. However, in these types of games the rest of the Achievements are sprinkled throughout your journey, sometimes rather generously, as is the case with a title like Kameo or Condemned, so you will continue to unlock a steady stream of Gamerscore as you make your way from point A (tutorial) to point B (final boss).
Collecting shiny objects and magical tokens is always fun, until you are down to the last one or two of course. Crackdown is a perfect example of this, where at first you are finding Agility Orbs left and right, but then after a while the discoveries slow to a trickle until eventually you're running around for days or even weeks looking for orb #500. Fortunately for Crackdown, traversing Pacific City is a great deal of fun in and of itself. Unfortunately for Achievement whores, running around in the virtual worlds of Harry Potter and Cars... not so much.