- Estimated achievement difficulty: 10/10 [7/10 for 935]
- Online: 41 
- Offline: 0 
- Approximate time to 1000: 80-100 hours [dependent on skill] [50-60 hours for 935]
- Minimum number of playthroughs needed: 1 [+2 Partials for the "Mastery" achievements].
- Missable achievements: No
- Does difficulty affect Achievements: Yes
- Unobtainable/Glithed Achievements: No
- Glitchy Achievements: No
- Extra equipment needed?: bungie.net account
DLC: The Taken King
- Difficulty: 7/10
- Time to 250: 30-40 hours
- Playthroughs Needed: 1 [+2 Partials for the class quests].
Destiny is a co-op shooter/RPG hybrid from Bungie. The game is set around a somewhat dumbed down MMO framework, and focuses on action and loot over story and substance. The game itself is grindy, as are the achievements. If that is not your type of game, Destiny may not be for you. If you love the idea of gearing up with friends and taking down waves of enemies and tough bosses, it's a very fun game.
Step 1: Setup
The first thing you'll want to do is create an account at bungie.net and link your Gamertag. This will be required to join a clan which is required for a few achievements later in the game. It is also worth bookmarking the Legend page which will help you track your gear, bonuses, daily/weekly missions, and weekly marks. Once you're set with that, load up the game and pick a Class that suits you. Once in-game, you are able to create or request to join a clan via bungie.net (inexplicably there is no clan management in-game).
To create a clan, visit this page online. To join a clan, you'll need the link to the clan or you can search by name, then click "Request to Join" - once one of the clan leaders accept you, you're in! Now that you've got your character all setup and in a clan, it's time to begin.
Step 2: Story
Play through the main story missions first, while looking for dead ghosts (Ghost Hunter achievement), gold chests (better loot), materials (Spinmetal, etc - Packing Heat/Fully Weaponized achievements), public events (Public Defender achievement), and Engrams (Decryptologist achievement), as well as completing bounties as they become available to level up more quickly. Try for as many precision shots as possible for the "Bane" achievements as well. You'll get a number of story related achievements and other miscellaneous achievements along the way without really trying.
Step 3: PVP
Once you have completed the story and leveled up a bit, you'll be ready for PVP. Because you use the same character from your story mode, starting this too early will leave you at a disadvantage against higher level players. You'll need to play 34-50 matches in a single week (34 if you win all of them, 50 if you lose all of them) to max your Crucible marks, and during those matches you should pick up all the other achievements as well.
Step 4: Strikes and Farming
Completing Strikes, earning rep from various factions, and farming materials to get higher level gear will help you level up to where you need to be for the final step of the game, the Raids. After Level 20, the only way to actually increase in "Level" is to equip gear with a "Light" rating. The amount of Light required for each level can be found here. You will also want to make some friends and/or join a large clan to work on the Strike achievements and ultimately the Raid achievements.
Step 5: Raids
Raids are hard. Like, insanely so. You will need a completely decked out character and five friends who are likewise geared to the highest possible standard. You'll also want to be in a clan with those friends, and be able to communicate and coordinate with them well during the missions. They are not too different from Strikes, though there is less direction from the game on what to do, and as I mentioned, the difficulty is ramped up significantly.
Step 5: Mop Up
You should not have much left to do achievement-wise, unless you never played the other two characters to get their Mastery achievements. If you're still somehow missing anything else, check the individual achievement descriptions for help. If you've cleared Step 5, you'll be able to get any other achievement with ease.
DLC: The Taken King
(Full G&RM Found Here)
The Taken King is the third expansion for Destiny, and by far the largest. It starts the second year of Destiny and brings with it a number of long-requested changes to the game that cut down on some of the grinding that was present in Year 1.
Step 1 - The Taken King Quests:
You will need a Guardian at level 25 to begin The Taken King's content. You will receive a Spark of Light from the Postmaster to boost a character to this level (which you can use for a secondary character if you already have one at 25 or higher). Once you log in, travel to Phobos in the Mars region to begin the quests. After the first story mission, you can complete the sub-class quest for your main character.
As you progress and complete the main story content, other quests will open up from Petra and Variks in The Reef and many of the characters in The Tower. Work on all of them to begin and complete the other quest achievements. A few can not be completed until you are inside the raid (Step 2). Collect the Calcified Fragments as you go. You will need 45 of the 50 available.
Step 2 - King's Fall Raid:
The King's Fall raid requires that the host be level 40 to begin, and it is suggested that the Light Level of characters be around 290, while you are able to enter at 270 (not recommended). Completing the raid on Hard difficulty will unlock both achievements, but you'll want to beat it on Normal first to familiarize yourself with the mechanics and gain some of its loot to help you on Hard.
Continue from Step 1 for the few quests that require actions inside the raid to complete both steps, as well as collecting the few Calcified Fragments found in the raid.
Step 3 - Other Sub-Class Quests:
You will need to each class at Level 25 to begin and complete their respective quests to unlock their third sub-classes. Do so for your other two characters to complete the final two achievements.
Note: If you unlock these achievements in one version of Destiny (be it 360 or One), you can load up the other generation's version and unlock them automatically without owning the content.
Note 2: Similar to vanilla Destiny, if you complete the requirements of an achievement and it does not unlock, use this method to force them to pop.
Note 3: Some of the quests are buggy in that the quest-giver will not have an indication above their head like they should. If you think a new quest should be available, talk to the person anyway and it will likely be there.
[XBA would like to thank The Pants Party for this Roadmap]