I love achievements, I think they are a very important part of a game. However, I do think that most developers don’t really know what achievements are supposed to be.
An achievement is, by definition of name, something hard or lengthy to accomplish. Most games have achievements as “Finish the Game”, which should never be placed as an achievement, because winning the game should be its own reward.
Instead, achievements should be used to point that you surpassed a very difficult situation, or you attained the maximum skill for said attribute (which should be, again, hard to accomplish), or maybe something truly amazing like the Life of a Wizard achievements, were one achievement actually does mean a lot–You had to win and play well from the very beginning to get most.
I don’t think there is anything wrong with the achievements for multiple endings, such as in Zombie Exodus, but I would still treat them as something separate. The ending itself should be the reward, and it should be called just that: Ending X (Insert number or title).
Now that’s just my opinion, but I am kind of an achievement hunter myself, and I know when an achievement is good or not.
Most of all, an achievement should depend only on the player, nothing that is out of his reach. It is O.K. to have achievements that contradict each other, if it is about replay-ability, but you should never make an achievement that depends on a variable such as a random number. If the player must go through a random event, make it so that the achievement itself is independent from it, in a way that every result allows you to reach it.
In another note, there is no platform or gallery where we can see all the CoG achievements we have won, and most games don’t have a section at the end for it. I think that is a flaw. Achievements ‘pop-ups’ were introduced way after ChoiceScript was made, and consequently most of the games, so it is reasonable to say that they haven’t made a user system were these achievements can be stored–yet.
Given this, I think it is a smart for any developer to actually give room, a section, just for the achievements, whether it be in the stats screen or just at the end. Both has its uses, and it depends on you how you choose to make you achievements screen.
Achievement screens at the end often reveal most of the things you can do at the game (that have an achievement tag on it of course) and may consequently ruin the thrill of looking for every other option. But at the same time, it can also provide indications of where to go on your next playthrough.
Achievement screens mid-game will often only register what the player has managed to accomplish so far, preferentially not giving any indication of how to gain the others, in order not to influence the character’s choices.
Perhaps, in the end, having both kinds would be best. It is up to how you choose to develop the feature, and what you want to be revealed or not and when.
Lastly, I think it is smart to note that most, if not all games, currently lose every progress of yours when you choose to begin a new adventure. Now, that is most fine, I tell you, but with the introduction of the achievements concept, it means that the player will have to track its accomplishments himself if he so desires.
I am sure it is possible to make something about this, and it shouldn’t be too hard to figure a solution.
Perhaps never truly resetting the game would do it–Only the main character and story variables would be put to default, and the player thrown to the beginning section, instead of using a Restart button. That would easily allow you to keep your achievements. Still, you have to think things through thoroughly (T^5) when taking this course of action, or you might just end up breaking the game after one or more playthroughs.
Keep in mind that this I thought based on the current model we have.