Achievement Flag Definitions

Table of contents:
Offline Game Mode
Online Game Mode
Online/Offline
Single Player
Cooperative
Versus
Host Only
Community
Main Storyline
Difficulty Specific
Stackable
Collectable
Missable
Cumulative +
Cumulative -
Level
Shop
Viral
Online Skill
Players Required
Time/Date
Multiple Playthroughs Required
External Content
Time Consuming
Buggy +
Buggy -
Partly Discontinued/Unobtainable
Discontinued
Unobtainable
Offline Game ModeThese achievements require play in game modes that do not necessitate a connection to any online services.
Offline game modes, such as single player campaigns or challenges, local co-op, and system link, do not require an active internet connection. This does not mean that it is necessary to be disconnected from any online services.
Online Game ModeThese achievements require a connection to live services, such as Xbox Live, for playing an online game mode, for sharing content, accessing leaderboards, or validating data with a server.
Online game modes are those which require an internet connection in order to play. This includes achievements that require community generated content that can be played in typical offline game modes.
Online/OfflineThese achievements can be obtained in either an online or offline game mode.
Achievements marked with this flag may be unlocked in either online or offline game modes, giving the player some choice in how they earn it. This flag does not necessarily mean that the achievement can be obtained in any and every mode in the game.
Single PlayerThese achievements can be obtained by a single player.
Single player achievements can be obtained in any mode which requires or permits solo play against AI opponents, such as campaign, instant action, bot driven modes, or survival levels. It also pertains to any action required by a single player outside of any game mode.
CooperativeThese achievements can be obtained by two or more players in a cooperative game mode who have met the achievement requirements.
This flag is applicable to achievements earned by players in cooperative game modes, such as campaign, bot driven modes, or multiplayer modes.
VersusThese achievements can be obtained by two or more players in a face off gamemode who have met the achievement requirements.
This flag is applicable to achievements earned by players in modes where they are intended to face off against AI or human opponents.
Host OnlyThese achievements are only earned by the host or primary player.
This flag is applicable to achievements which will only unlock for the leading or primary player when the achievement requirements are met.
CommunityThese achievements can be unlocked by interactions with a community.
This flag is applicable to achievements where the game mode requires interactions with other gamers while not being simultaneously in the same game mode. These interactions are social by nature and usually are indirect online interaction such as auctions, content sharing, voting, or challenges sanctioned by yourself or other players.
Main StorylineThese achievements are gained automatically by progressing through the main game mode.
Main Storyline achievements are guaranteed to unlock in the course of the primary playthrough of the main game mode or storyline, and therefore do not need to be specifically sought out. In games where it is unclear what the main mode is, the flag is not used. If the game features a cooperative mode, achievements tied to progression through this mode are also applicable for the Main Storyline flag.
Difficulty SpecificThese achievements require that the game be played on a certain difficulty level.
Difficulty Specific achievements ask the player to complete some objective, often to clear the game or a level on a certain difficulty setting. This flag is excluded from the lowest difficulty setting where the difficulty specific achievements have the Stackable flag applied. The Difficulty Specific flag does not refer to more specific options like disabling driving assists, respawns, or to challenging constraints on play style, performance, or skill level.
StackableThese achievements can be unlocked at the same time as, or in the course of, earning its more difficult or less difficult counterpart.
The Stackable flag is applied to any achievement that can be unlocked by fulfilling the requirements of a similar, more difficult or less difficult achievement. Aiming for the most difficult achievement first is most efficient, since doing so unlocks the easier achievements as well. The flag is used only when attempting the harder versions later results in duplicating effort, not in cases where the easier achievements are mere stepping stones on the way to unlocking the harder one(s).
CollectableThese achievements are obtained by exploring the game environment to find a set of unique objects.
Collectables come in a variety of forms; they are not necessarily items to be picked up, but may also include other kinds of objects that can be interacted with in the game world. In general each object can be distinguished from the rest by its location, number, or some other identifying means. This excludes items or actions that require all to be collected or interacted with in a specific sequence.
MissableThese achievements can be missed.
An achievement is flagged as Missable if it is possible to bypass all opportunities to unlock it in a given playthrough. The flag is not applicable to achievements that can be reattempted by using a level select option nor to achievements that specify sequential actions ("in a row"), or games which do not have a clearly defined main mode.
Cumulative +These achievements are obtained by repeatedly performing the same action or set of actions over time.
Cumulative + achievements involve a counter which increases whenever the player performs a relevant action or set of actions. It does not constrain players to perform actions consecutively, in a single match, before time runs out, or within other similar limitations. Progress should not suddenly reset to zero except in the case of a glitch.
Cumulative -These achievements are obtained by repeatedly performing the same action or set of actions over time, but progress can diminish
Cumulative - achievements involve a counter which increases whenever the player performs a relevant action or set of actions, but can decrease over time or as a result of other actions. It does not constrain players to perform actions consecutively, in a single match, before time runs out, or within other similar limitations.

In some instances money, or other in game currency, needs to be on hand in order for the achievement to be obtained.
LevelThese achievements must be obtained by levelling up in-game components.
Level is applied to achievements that require a specific level, rank, or experience point accumulation to be reached at the time of unlock or as a prerequisite.
ShopThese achievements require the purchase of an item or a series of items as prerequisites from a shop.
A Shop achievement must be earned from buying items from a shop which includes purchasing game components, such as characters, weapons, or costumes. This is also used for buying abilities to upgrade a character or a weapon where you have an in-game currency that must be used to purchase them. This excludes items which are not guaranteed purchases or which are crucial to advance in a playthrough.
ViralThese achievements are obtained by contact with a player who meets the requirements for spreading it to others.
Viral achievements are those which spread throughout the online community as people play games together. In order to spread a Viral, one must be a permanent member of a special group of players. These include the group of players possessing the viral achievement, owning another special achievement, being officially affiliated with the game (e.g. developer, moderator) or permanently holding a specific rank or title.
Online SkillThese achievements require a certain TrueSkill rank or a certain position on a Leaderboard to be reached.
The Online Skill flag exists to inform players that an achievement compares online performance with other automatically assigned players. The TrueSkill system allocates a rank based on win/loss records; the more games that have been played, the harder it is to change rank. Therefore, players must plan carefully or they will make it harder for themselves to get the achievement.
Players RequiredThese achievements require a minimum number of participating players to attempt.
This flag alerts players that a group of a minimum size, either players or controllers, is required. Some games may not start or track progress without enough players, or feature requirements that are impossible with too few players.

Note, only achievements that need three or more players will have a version of the Players Required flag assigned.
Time/DateThese achievements require you to play the game or perform actions at certain times, within a time limit, or on specific dates.
This flag warns players that an achievement can only be earned on specific occasions, at certain times, playing a number of days in a row, or within a clearly defined time limit.
Multiple Playthroughs RequiredThese achievements cannot be earned during the initial playthrough.
This flag indicates that you cannot earn the achievement during the first playthrough of a game. To earn these achievements you will need to restart the game after completion or continue into a “new game +” mode. This excludes choice based storyline achievements.
External ContentThese achievements require content outside the game or input devices other than the system default.
This flag is applicable to achievements which require content beyond a copy of the game, excluding DLC, or additional peripherals, other than the system default.

These may include, but are not limited to, the following: Redeeming an online pass, a save from another game, a normal or full third party account, Other controller options, such as Kinect Sensor, uDraw tablet, or musical instrument

DLC and required TU’s are only considered External Content when one DLC requires owning another separate piece of DLC.
Time ConsumingThese achievements require at least 20 hours of play time to obtain.
The Time Consuming flag is applied to achievements that require at least 20 hours to unlock, not counting time spent on progress towards Main Storyline, Multiple Playthough Required, or Missable achievements. Achievements which could take an indeterminate amount of time depending on skill or online activity are measured by how long an achievement takes to boost.
Buggy +These achievements may unlock before the requirements have been met.
Buggy achievements are those which do not behave as expected. Some buggy achievements will unlock prematurely before the requirements have been met or at seemingly random times others will unlock after performing a completely unrelated task.
Buggy -These achievements may unlock after the requirements have been met or not at all.
Buggy achievements are those which do not behave as expected. Some buggy achievements will unlock unpredictably after the requirements have been met and exceeded, others will unlock after performing a completely unrelated task, and a few will be unobtainable for certain players, but not others.
Partly Discontinued / UnobtainableThese achievements may no longer be obtainable by players who have not already met specific requirements.
These achievements may no longer be obtainable by players due to closed servers or game version requirements but may be obtainable for some who had previously met the requirements. Those who have met the requirements before the discontinuation of the game related service, those living in a specific region, or those playing pre/post patch may still be able to unlock these achievements.
DiscontinuedThese achievements can no longer be obtained due to closed servers, a bad patch, or other unusual circumstances.
The Discontinued flag is used to mark achievements which used to be obtainable but are now impossible to unlock legitimately. This does not include achievements that are difficult or inconvenient to obtain due to changing circumstances such as the presence of leaderboard blockers or a lack of multiplayer activity.
UnobtainableThese achievements have never been possible to unlock legitimately.
For an achievement to be marked as Unobtainable means that it can never be awarded even when the stated requirements have been met, or that it is literally impossible to meet said requirements. This is almost always due to programming flaws in the game, but in some cases it reflects the fact that content necessary for the achievement has not been made available. If a patch fixes the game code, or the missing content is released, the flag will be removed.