Assassin’s Creed III is out and it is, by all accounts, an awesome game that lives up to the strong premise of its predecessors and then some. The game offers more in terms of combat, storytelling, and traversal as you take on the role of Connor Kenway, a half-Native American Assassin who finds it in himself to bring justice to the frontier during the age of the American Revolution.
Like the previous games in the Assassin’s Creed series, there’s plenty of things for you to unlock as you progress through the game, accomplish missions, and unlock memory sequences that not only serve as the game’s chapters but also provide you with indicators of your progress through Desmond’s genetic memory of Connor Kenway.
If you consider yourself a completionist*, then you’ll find great use of the guide beyond to aid you in unlocking everything in Assassin’s Creed III.
*completionist
-
a person who feels compelled to discover and unlock every bit of content in a videogame.
Unlockable Outfits
The biggest unlocks—or at least the most interesting ones—come in the form of outfits for you to dress Connor up however you please. These range from location-based outfits as well as a few special ones that you can only get by accomplishing more difficult collection tasks. Here they are in full:
Sequence 06
Boston Outfit
Jamestown Outfit
Charleston Outfit
Sequence 07
New York Outfit
Philadelphia Outfit
Baltimore Outfit
Complete all Optional Objectives
Altair's Outfit
Complete Oak Island Naval Location
Captain Kidd's Outfit
Complete Achilles' Painting Mission
Achilles' Original Outfit
Collect all Feathers
Kanien'keha:ka Outfit
Uplay
Ezio's Outfit
The Uplay Outfit has to be unlocked through Ubisoft’s Uplay achievements system, so be sure to sign in to claim it. Here's what it looks like in combat:
Multiplayer Characters
In addition to the single player costumes, you’ll have the opportunity to unlock a host of costumed characters by playing through the campaign. Some of these characters are harder to get and will require you to collect specific mementos (detailed below)
The characters you can unlock include
William Johnson Patron, John Pitcairn Patron, Thomas Hickey, Charles Lee, Benjamin Church, Haytham Kenway, and Israel Putnam.
Certain characters must be unlocked by acquiring hunting mementos, which you can get from completing hunting challenges. These include the Black Bear Hunter, the Wolf Hunter, the Cougar Hunter, the Elk Hunter, Bobcat Hunter, and the Deer Hunter. Completing every hunting challenge will unlock the Master Hunter.
Finally, completing the game's single player campaign will unlock the Huntsman character, whom you can see below. 
Assassin Recruits
Just like in Assassin’s Creed Brotherhood and Asssassin’s Creed Revelations, Connor will have the ability to recruit new Assassins to aid him in his task. Each of these assassins comes with his or her own special ability, allowing you to use them to great effect during missions.
Here’s where you’ll find each of them and what their abilities are.
The first of the recruits, Stephane Chapheau, can be found in Sequence 6, Memory 2. You’ll have to play through the mission to acquire him, from which point on you’ll be able to recruit other special assassins.
Completing the various liberation missions in North and South Boston, and North, East, and West parts of New York will unlock the following Assassin recruits, whose abilities are as follows:
Duncan Little, Bodyguard
Clipper Wilkinson, Marksman
Jamie Colley, Ambush
Jacob Zenger, Covert Escort
Dobby Carter, Lure Away
Treasure Maps and Chests, and Keys
As it is with all the previous Assassin’s Creed games, you can purchase maps from stores to acquire the locations of treasure chests on each map. Getting to most of these chests is easy and requires some amount of traversal. The rewards contained in each chest appear to be randomized, so simply open them whenever you come across them.
It’s a good idea to clear a location of chests before moving on to the next or you’ll end up having to backtrack through locations to find those you missed.
You’ll be able to purchase maps once you’ve unlocked it in Sequence 04. Storekeepers will carry maps for each of the locations in the game, as well as feather locations for Lexington, John's Town, Monmouth, and Black Creek. Additionally, some vendors will sell you maps containing the locations of trinkets and almanac pages.
To unlock these chests, you’ll need to complete certain missions or sequences to acquire their keys. You'll have to pass Sequence 05 to acquire the Frontier key, and Memory 02 in Sequence 06 for the Boston Central key. Completing the Liberation missions in Boston and New York will give you the keys for each of those locations.
Unlike previous Assassin’s Creed titles, you’ll have the opportunity to take on naval missions this time around. In addition to those seabound missions, you’ll have the chance to visit naval locations that are only accessible by sea. To find these locations, you’ll have to discover hidden letters and acquire trinkets.
Mementos
Mementos are things you can collect throughout the game. Most mementos get unlocked as you pick them up during mission sequences, so keep an eye out for newspapers and paintings. Some mementos require you to complete challenges. You can review each of these mementos in the Manor, where they’ll be showcased.
