Currently, the game is experiencing issues regarding achievement tracking. Until that's fixed, I suggest that you leave a trail of save checkpoints BEFORE and AFTER most events in case achievements stop getting tracked halfway. This will allow you to restart the program and get it back in working order without having to replay much of the content due to achievement gaps.

I ended up with way more saves after finally completing the game for the first time. Thankfully, this saved me from a ton of backtracking/replaying.

I do hope that this guide will give you the foresight to know when to save for the cruical bits (achievement-wise).

Today (01/08/2014) I tested out how achievements behave in MP.

From what I was able to observe, it seems that only achievements obtained within combat work (Surrounded, Running The Gauntlet, etc). Achievements for winning using certain conditions (Of Pens And Swords, etc) do not .

The testing was done in Network MP but not in Hotseat.

(you're all welcome to contribute helpful links)

The following links contain critical information used/referenced in creating this guide. Thanks to the swift replies of the Developers and the community's curiosity, this guide was made possible.

**The links below may contain massive spoilers. Proceed at your own risk.

Hint for 'A Sorry Bunch'

Classes and their usefulness

What is an escape battle?

Gameplay Tips from a Developer

Decisions and their impact on the story

Amazon Camp Location

Earning Money for the Best Ending (and achievement) - Part 2 (similar topic, different thread)

Gilded Gate Event (solution)

El Dorado - Risky Rewards - Part 2 (similar topic, different thread)

Fountain of Youth Location

Click to enlarge the maps. They are labelled to a certain degree.

-----

Hispaniola



Mexico

Feminist
Start the game with only women, as a female character


Self-explanatory. At the start of the game there will be adequate selection of followers to pick from in order to get an all-female expedition group started.

Wake-Up Call
Lose the first tutorial battle


Easy achievement. Just keep skipping your turn.

Mestizo
Recruit Isabela de Yruenes for your expedition


Your opportunity to recruit Isabela will become available right before you leave Santo Domingo. Simply give her a chance during the conversation and she will get to join your expedition.

The Wrath Of God
Experience a mutiny


A mutiny is easily achieved by simply starting up a new game and starving your followers. It'll require their morale to go in the negatives before it triggers.

Surrounded
Kill an enemy with a flanking strike


This should come naturally while playing but for those of you who have yet to learn this mechanic, a flanking strike is performed when you attack an opponent surrounded by 2 of your units that are directly opposite of each other.

(see bottom left portion of the image below)

Ambassador
Resolve the Jungle Drums goal without bloodshed


Jungle Drums is one of the very first quests you will be tasked with. North east of Santo Domingo you will find natives performing a ritual at a ruined Temple. You'll get this achievement if you fully take advantage of diplomacy and respect their traditions.

Having a high amount of diplomacy (the statistic) helps with your chance of success. Just remember to save in the event that it fails.

Pot Shot
Score a hit with a ranged attack with a 5% hit chance


A good time to try this (without much consequence) is during one of the tutorial battles wherein barricades are introduced. You can mostly turn the battle into a gun fight so your chances at getting this achievement will increase. Remember to save your game before the tutorial.

The reason why I suggest doing this in a tutorial battle is because you don't have to worry about any lasting consequences for any of your actions. You can do this while playing regularly but it is counter-intuitive to attempt attacks that have a 5% chance of success in a real battle.

Juggernaut
Enter combat with at least 25 points of Equipment assigned to a single unit


A follower can enter combat with more equipment points if you promote them. Soldiers in particular have the highest capacity for equipment.

A Veteran rank Soldier will be able to fulfill the 25 point requirement.

Champion
Win all three battles in the Tournament


After one of the tutorials in Santo Domingo, Noriega will ask if you want to arrange a tournament competing against his soldiers. If you agree, the tournament will be available further into the story in roughly the same area.

The tournament consists of 3 battles. The 3rd battle is optional so be careful not to accidentally reject it. The achievement will unlock after you win the final battle.

A Sorry Bunch
Have all your followers be disabled at the same time


The most efficient way to get this achievement comes in the form of an event in Mexico. A place called Ancient Temple can potentially disable your entire group if you choose to loot it.

http://steamproxy.com/app/237430/discussions/0/648811852366244944

Harsh Rationing
Make camp without giving any of your followers food


While setting up camp (C), set the rations to nothing and assign it to all your followers. The achievement will unlock after finalize your decision.

The Bigger They Are
Defeat Esteban Gallego


Story-related.
This achievement is unlocked for beating Esteban Gallego.

Infected Mushroom
Complete The Gloaming


The Gloaming is the second side quest given by the Church in Santo Domingo.
There will be a battle portion regardless of whom you choose to fight (yourself or the shaman).

Don Quijote
Complete 5 side quests in Hispaniola


Simple achievement. It's obtained by completing sidequests such as Flotsam, The Gloaming, The Medallion, etc. Personally I unlocked the achievement during Flotsam. It popped right as I completed the first portion of the quest.

The Boot
Kick an enemy into a burning or trapped space


To get this achievement, you have to use a Hunter's basic skill (Rebuke) to push an enemy into a trap.

A-Team
Enter combat with six units at Veteran or higher rank


Self-explanatory. Keep in mind that experience is only gained from events. Battles don't necessarily give experience (the completion of the event is what counts). This means you can take the peaceful/diplomatic route and still get experience.

It takes a total of 400 experience to get a Recruit promoted to Veteran.

Number One
Promote a follower to Lieutenant


Self-explanatory. I suggest doing all the side quests from the various settlements in Mexico. If you complete all/most of them, you're sure to have more than enough experience to get a Lieutenant.

It takes 2000 xp to promote a Recruit all the way to the top.

A Friend In Need
Save Governor Bernardo De Manzanedo


Story-related. Your chance to save the Governor will come when Leandra attacks Santo Domingo.

Skull Crusher
Deal more than 100 points of damage with a single attack


There are a few factors that will assist you in unlocking this achievement...

• Enemy Rank/Defence
  
• Character Rank/Offence
  
• Character Traits
  
• Flanking Strike
  
• Debuffs (if applicable - optional)

The best scenario & enemy to get this achievement would be an encounter with the Taino stealing from your camp. They are easily the weakest enemy you'll encounter in the game. All the natives are Recruit rank and they have low defense. They won't fight back as well so there's barely any risk involved.

Veteran followers are required to deal this much damage. I suggest a Scout/Hunter/Polearm Soldier.

If you are using a Hunter, make sure to have Keen Eye (7 points of armor ignored) and Sexist (+10% damage to opposite gender).

If you decide to go with a melee unit, take advantage of the Flanking Strike upgrade (from 15% to 25% bonus) instead of the Sexist damage bonus.

Triage Hero
Nurse a Fatally Injured expedition member back to full health


You will have several opportunities to nurse a fatally injured follower back to 100%.

Your chance will come either from a battle wherein your unit gets incapacitated for a long time OR during a scripted event.

Example: A bit later in the Hispaniola storyline, Esteban will try to kidnap and offer one of your followers to a group of cannibals. This event will get one of your followers fatally injured after getting ambushed by Esteban's soldiers.

Tactician
Achieve fifteen Flawless Victories in a row on Normal or greater difficulty


Self-explanatory. The great thing about this achievement is that you can reload an earlier save game if you feel like you are going to get incapacitated.

You can also reload easy battles to have them counted towards the achievement all over again. For example, there are 3 battles in a tournament held in Santo Domingo. If you found all 3 battles easy, you can keep redoing them for the achievement.

El Loco
Attack and destroy a native settlement on Hispaniola


You can choose to attack the Jungle Village in Hispaniola to get this achievement. It's located east of the Ruined Temple. The achievement unlocks right after you defeat the natives.

Close Call
Revive an incapacitated unit and keep that unit alive until the end of the battle


The best time to do this is after you incapacitate all enemies but one. This way you can which of your followers go down and for how long.

Cartographer
Find all cairns on Hispaniola and compile all the maps of the island


Cairns are marked on the map as points of interest.



Once you complete all of cairns for one map (there are 3 maps total), you can compile it through the camp menu. This achievement is for the Hispaniola portion of cartography.

Treading New Ground
Find all the cairns and compile all the maps of Mexico


Just like with Hispaniola's cairns, you can view them on the map as points of interest. The only difference for Mexico is that the map is significantly larger.

Onwards To Glory
Cast off for the mainland!


Story-related. You can cast off for the mainland once you complete the main quests in Hispaniola.

Collateral Damage
Hit one of your own units with AoE damage


To hit your own unit with AoE damage, you need to use a lamp and drop it directly on your follower.



Another way to get the same result is to use the Trapper's Hailstorm ability. You'll have to wait until you get to Mexico before you can use this method.

Building Bridges
Marry a native


You can get this achievement by accepting the marraige scenario in the Pearl Fishers village.

Tame The Beast
Capture Xochiyohua


There will be a cave east of Xapala. This cave houses a large jaguar called Xochiyohua. Setting up a net trap should catch it and earn you the achievement.

Fleet-footed
Achieve a Flawless Victory in an Escape battle


Your first escape battle occurs after you visit Xalapa. If you decide to take Anacaona with you, the battle will be triggered. Simply get everyone across without getting incapacitated to unlock the achievement.

Diplomatic Asset
Recruit Anacaona for your expedition


You'll be able to recruit Anacaona after speaking to the chief of Xapala. Anacaona will ask you to accept her into your expedition. If you accept, you have to complete an escape battle first before the achievement unlocks.

Running The Gauntlet
Kill an enemy with an Interrupt attack


An interrupt attack is a tactical move that can be used to react to with ranged attacks against enemies that are closing in. Ranged attackers automatically attack (once) when an enemy moves within 6 cells of your unit.



Just like with Close Call, it's easier to do this when there is only one enemy left.

Among The Prickly Pears
Discover Tenochtitlan


This achievement unlocks after you talk to the guard blocking entry to the city. Tenochtitlan is automatically marked on your map if you talk to the first 2 villages when you arrive in Mexico.

The Greater Good
Sacrifice a member of your expedition


In Tenochtitlan, there is a huge building (Tenochtitlan Temple) wherein you can sacrifice a member of your expedition for the achievement.

The Beginning Of The End
Inadvertently unleash smallpox on the population of Tenochtitlan


There is a house near Tenochtitlan wherein a Shaman will give you a quest to bring someone infected with smallpox back to his home.

Raider Of The Lost Temple
Complete The Temple of Death


The Temple of Death is located southwest of Xalapa. It's quite far and nowhere near a road so expect to camp a few times to get there. Once you reach the temple, you'll have to keep progressing all the way to the end in order to get the achievement. There's about 3 decision points before that happens.

Cannon Fodder
Kill an enemy unit with a cannon blast


Keep Your Distance
Win a non-tutorial battle without ever getting within melee distance of an enemy


First off, the cannon is located north of Xalapa (along the road). You'll have to repair it first before being able to use it.

I strongly suggest using the cannon in the quest Protect the Envoy. The battle terrain there will be advantageous for AoE attacks. If you use this method, you can easily get the Keep Your Distance achievement as well.

For this scenario, you will need...

• At least 4 Barricades
  
• 5 Cannonballs
  
• A set of traps of your choosing (Torch/Lantern/Spike/Net Trap) depending on your battle composition.

*If you have a Veteran Trapper, you can most likely end it with just the Barricades and Cannonballs due to Hailstorm.
**For extra damage insurance, bring Lanterns.

Battle Composition

• 1 Veteran Trapper (if available)
  
• 1 Man-at-Arms Scholar (for the damage buff)
  
• 1 Doctor (optional and replacable with Hunter)
  
• 1 Hunter

*If you don't have a Trapper, you can just stick with Hunters.

When you start the dialogue at the diplomatic site, scout the area, scavenge for barricades, and fortify the entrance. This will allow you to place your traps as close to the enemy as possible (due to having 2 units in front. Make sure your trapper (if you have one) and your other strongest unit are in front before the battle starts.

Set up your Barricades, Cannon, and etc as shown in the screenshot below.



The 4 Barricades will absorb at least 8 attacks total so you'll have a few free AoE attacks at your disposal. The rest of the process should be pretty ovbious. If done right, the enemy will be dead or close to death before they can reach your first 2 units. Just don't forget to use the Scholar damage buff at least once (if available).

The Dog-Headed God
Discover the Masaya Volcano tunnels


The Volcano tunnels is located south east of the village. You'll need to complete a quest before getting there.

The City Of Gold
Discover El Dorado


To 'discover' El Dorado, you first need to complete an event (mini-puzzle) called the Gilded Gates.
http://steamproxy.com/app/237430/discussions/0/846962626990554073/

Apocalypto
Aid the escaped slaves


You'll encounter the escaped slaves south east of Tenochtitlan.

(not the exact location but they will be in the proximity of the area)


It will be in the form of a native running away from your expedition. Keep following them and you'll have the option to help. The achievement is awarded after a battle.

Of Pens And Swords
Win a non-tutorial battle with only Scholars and Doctors


Since fighting and winning a regular battle with only Doctors and Scholars is generally a bad idea (inefficient), the next most logical solution would be to obtain this achievement through an escape battle. The escape battle in question is the one that occurs after you allow Anacaona into your party. There will be 2 escape 'cells' near your spawn point to get you a victory.

Here's the quote from when I asked about the achievement:
http://steamproxy.com/app/237430/discussions/0/630800446933515086/

Originally posted by Nova:

As for the Xalapa fight, it's definitely doable. The conditions for winning is that you have to have all your standing units in an escape zone at the end of a fight, but you don't have to bring 6 units ;)

To get this achievement, I used 2 Doctors and 1 Scholar. If you have more doctors/scholars then use them as bait. I made sure that at least 1 of the Doctors was able to revive (as a contingency plan) and that the Scholar was either a Veteran or Sergeant (for the Logistics movement bonus). Remember to also make sure to use your tactical move to avoid attacks of opportunity when possible.

Hogar Dulce Hogar
Rebuild Fortaleza De Gutiérrez


The fortress is located along the road west of Xalapa. You'll need to clear it out before you can rebuild it. It will require valuables and one of your followers for a set amount of days.

Don Juan
Form a romantic relationship


Depending on your character's gender, you'll have the option to romance either Coyotl or Citllali (both recruitable followers). Make sure to pay close attention to their Morale since it can potentially get in the way of the romance arc.

This will happen if you pursue marriage and romance in the same playthrough (minor event). It's nothing to worry about though.

Originally posted by Jonas:

If you marry Tayanna/Cacama and still go through the romance arc with Citlalli/Coyotl, they'll get in a fight later.

The Waters Of Rejuvenation
Discover the Fountain Of Youth


The Fountain of Youth is located north/north west of Miguel's shack (Far NW on the map). The event will require 3 different followers to accompany you (they will get injured). Although they get injured, the well will(?) heal them after the event is concluded.

Historian
Unlock all the Codex entries


Codex entries are unlocked for discovering/completing parts of the game. There are 24 in total. This will come naturally if you plan to do 100% completion. The final parts of the storyline do not contribute towards the Codex so you can get all of the entries before the final missions.

Artisan
Fully research all the possible inventions and construct one item of every possible recipe


In order to get this achievement, you'll need to fully research all inventions and construct all items.

This will take a lot of camping AND level 10 Tinkering. Make sure to invest at least some experience towards your scholar (they specialize in Tinkering as their main stat).

If you are having trouble accumulating the necessary materials to build all items, you can wait for your fortress to be upgraded with a workshop. The workshop will supply you with various materials of your choosing on a regular basis.

Merchant
Trade at every market in both campaigns in a single playthrough


Hispaniola Campaign:

Santo Domingo Market
Higuey Village
San Tiago Market
Quintara residence (right above San Tiago)
Fishing Village
Jungle Village

Mexico Campaign:

Swamp Village
Masaya Village Traders
Tenochtitlan Market
Aztec Farm - farm right above Tenonchtitlan (can be wiped out)
Cuautitlan Market
Xalapa Market
Totonac Village
Totonac Merchant - these merchants run a regular route around the roads near Xalapa
Papantla Market
The Amazons - the camp moves around a bit
Fortress Trader - unlocked after upgrade

Check the map section of this guide for visuals.

Magnetic Personality
Recruit all 6 native followers in Mexico in a single playthrough

Originally posted by Jonas:

Cacama/Tayanna, Trapper, Mexico, The Pearl Fishers
Anacaona, Civilian, Mexico, Xalapa
Necalli, Warrior, Mexico, Fortaleza De Gutiérrez
Patli, Shaman, Mexico, Tenochtitlan ("The Spotted Curse")
Citlalli, Amazon, Mexico, The Amazons ("Kill Citlalli" / "Kill Momoztli")
Coyotl, Champion, Mexico, Texcoco ("Silence Coyotl" / "Raid the Market")

In order to get all of the native followers, you have to..

• marry Cacama/Tayanna
  
• agree to take Anacaona with you
  
• progress the Totonac storyline up to the Aztec farm razing (so that Necalli appears at your fortress tavern)
  
• complete Patli's quest and allow him to keep talking (so he suggests joining you)
  
• choose not to kill Citlalli and kill Momoztli instead(?)
  
• choose not to kill Coyotl and show compassion and/or generosity for the people he's feeding

Stronghold
Restore Fortaleza De Gutiérrez to its full glory


This achievement requires you to fully upgrade the Fortress. It will cost a significant amount of valuables and several camping days to completely do so.

WARNING: Make sure to do all your upgrades before you pick a side (Aztec/Totonac). I encountered a bug wherein my upgrade progress completely stopped due to starting the war.

La Noche Triste
Kick off the battle for Tenochtitlan


Story-related. This achievement unlocks when the final set of battles start.

Fall Of The Empire
Kill Moctezuma Xocoyotzin


Defying History
Save Moctezuma Xocoyotzin


These 2 achievements are tied to the story. Depending on which side you choose (Aztecs or Totonacs), you can either kill or save Moctezuma.

Conquistador
Turn against your allies in their hour of triumph



In order to qualify for this event, you need an army size of 500 soldiers. In order to get that many soldiers into your Fortress' Barracks, a fully upgraded Stronghold is needed. Anything lower cannot house all those soldiers.

With all of those conditions met, Noriega will call for you after the final battle with the opposing faction to start the Conspiracy quest. The achievement will unlock after the very final battle (your betrayal).

NOTE: This achievement only unlocks if you betray the Totonac chief. (tested)

Cortés
Complete the game on Normal difficulty


Pizarro
Complete the game on Hard difficulty


Aguirre
Complete the game on Insane difficulty


Self-explanatory. The lower difficulty achievements get unlocked for completing the higher tier. If you're doing it on Insane, I strongly advise against enabling Iron Man mode. That's best left for the lowest difficulty if you are looking for efficiency.

No Man Left Behind
Return to Spain without losing any expedition members


Just as the achievement says, you must return to Spain without losing anyone throughout the entire campaign. That means avoiding fatalities, mutinies, sacrifices, etc. Fortunately, save files are your friend.

The Ecstasy Of Gold
Return to Spain with 50,000 Valuables or more


The most reliable way suggested by a lot of people is to use contextual activities for making money.

Fishing in general is very easy because guarding and hunting difficulty around the shore line is usually set to low. That means you can preserve a lot of food to sell.

You can also collect herbs (contextual) and turn them into medicine for even more trading power.

This method is quite slow but it's entails the least risk.

In order to save your valuables from getting stolen, store them in your fortress until the time is right. Be sure to also save regularly once it's time to farm for the valuables. The more valuables you earn, the more of it thieves can steal in one go.

Masochist
Complete the game in Iron Man mode on any difficulty


This achievement can be done on easy difficulty. I am unable to test if it works with custom difficulty setting.

The biggest advice I can give is that you don't need to finish the entire Mexico campaign. As soon as the Port becomes visible/available on the map, you can depart for Spain and claim this achievement.

As posted by a dev:

Originally posted by Jonas:

The port appears when you rebuild the fortress.

One thing I noticed was that the fortress defense fight had 18 enemies instead of 12. i suspect this was because I didn't bother upgrading the fortress during this run.