Since I've already spent most of this week talking about game length and how players themselves try to get more mileage out of their titles I thought that it was only logical to look at one of the most popular ways as of late that game designers and developers are adding incentive to play longer and try harder: in game achievements and milestones.
From a technical standpoint, gaming achievements are nothing new; beating a game always has been and always will be an achievement after all. The same can be said about getting to the highest level in an RPG, or getting the ultimate weapons in any given game. Of course the only reward for these things used to be the thing in and of itself: the ultimate weapons were worth getting because they kicked ass, and of course when you start a game you will generally want to see it through to the end. Starting with the last generation and then really hitting full force in this one is the relatively new phenomenon of in-game achievements: in other words, rewards (or at least platitudes) for completing certain objectives and tasks in game.
It's quite uncommon to actually see a game without achievements these days, especially one with an online component. Even a fair deal of flash games on sites like Newgrounds and Kongregate can have achievements for things as simple as actually clearing the game to ones that are a fair bit more complex like having a perfect run or coming in under a certain time which is often somewhat prohibitive to achieve. Hell, there's even the flash game series "Achievement Unlocked" where the only point of the game is to get achievements, and the game ends once you've achieved everything.
The Achievement Unlocked games though are obviously satire. The thing is, they are a satire that came about in part due to what many people have viewed as an over-saturation of achievements in games. Most achievements in console and PC games track things like difficulties beaten, or number of enemies killed. A fair bit of them do happen to overlap with the actual progression of the game itself, so simply by playing you're likely to get a handful of them. Other things though, like getting all golds in side missions or beating a ridiculous number of enemies though are obviously there in order to compel players to play the game long after they've initially cleared it.
Most of the time achievements are innocent enough; you can ignore them if they involve doing something that isn't your cup of tea, or you can try and get them all if you're a completionist. However, in the case of the latter sometimes achievements do hurt. There are instances where achievements require completion of certain events that are only available at certain points during a playthrough. An example of this is the Treasure Trove achievement in Lost Odyssey, which requires a perfect run through of all the treasures in the game. You can see just from the comments that this achievement is incredibly hard to attain, and in the case of some people has probably stalled their progress through the game due to not wanting to miss anything in order to actually get the achievement. This is pretty much a case of an achievement actually hampering the gameplay for a select group of players.
I know that a lot of you are just saying "Well, why can't they just ignore that achievement?" but for some people it's just more than a compulsion or a goal: it's something they have to do. Adding achievements to games has driven some people into gaming stagnation: they don't move forward from a select few games because they can't get all the achievements therein, and it keeps them from engaging in new titles.
Of course this isn't even going into the fact that achievements don't actually do anything in most cases. Although in some games like Team Fortress 2 some unlocks can be obtained through achievements (although they can be gotten just about anywhere else as well) most achievements are just there for show. And show they do: although it's not an epidemic by any measure, there are plenty of people out there that put way too much stock into their gamerscore or trophy collection, to the point where they get friends to help them get certain multiplayer achievements that it would be otherwise impossible to get, effectively scamming a system for no real point other than to show off "how pro" they are because they have a hard to get achievement (that's been obtained through no effort on their part). Like I said it's not a huge problem, but the fact that it exists at all is still quite an annoyance to those that just want to play their game without being hassled because they haven't unlocked the "mega death murder crap" trophy.
It's really a double edged sword. Achievements are still new enough that some of the kinks are still being worked out of the system, and hopefully there will be improvements. There's going to have to be, because it doesn't look like achievements are going anywhere anytime soon. And whether you like them or loathe them, odds are you're going to be getting some unlocks at some point in the future.