Unlike God Eater 2 Rage Burst, God Eater Resurrection is easier to finish. Since I haven't seen any english guides on how to 100% this game in steam, I took it upon myself to make one for the sake of convenience. In this guide (Excluding the Story & Natural section), I will try and give you the fastest method on getting the achievements.

A little disclaimer, I don't claim this guide to be totally perfect. If you have something to share that might help improve this guide then feel free to reach out to me or comment your ideas down below and I'll add it to the guide. Of course, proper credits will be given to those who have contributed.

Some things to take note of:
1.) Achievements that are obtained through missions do not immediately unlock upon fulfilling the requirements. You have to successfully beat the mission before it unlocks.

2.) All methods pertaining to achievements that require grinding in this guide are heavily reliant on overpowered bullets. So I encourage everyone to learn about them since it will help you a lot. If you want to learn more, here is a guide I specifically made that introduces them.

3.) Achievements do not unlock in offline mode. Make sure to play with an internet connection or you might miss some achievements and may have to create a new avatar just to get them.

These are the achievements that you will naturally get as you progress through the story of the game. I've also included the achievements that you will eventually get as you play and combined them with this section.

If story achievements do not unlock:
I've seen people in the forums discuss about story achievements not unlocking. When this happens to you, just go to your room's terminal and rewatch the cutscene that triggers it.
sources for this fix here:
source 1
source 2

Note:
1.) (for story related achievements only) for the sake of preserving the story experience, I will only state when these achievements will appear.
2.) I've provided the title of the cutscenes you need to rewatch if it doesn't unlock for you. The ones marked with an * means it is subject to change, If you don't mind I would like your help in confirming which ones are the correct cutscenes to watch.

1.) God Arc Compatible

- Pass the aptitude test.

This is the achievement you’ll get once you start the game. The achievement should appear once you enter the den for the first time.




2.) Resonance


- Perform a resonance between New-Type God Eaters.

This achievement will unlock in Difficulty 3.
If Achievement does not unlock rewatch: Resonance




3.) A New Leader


- Assume the role of 1st unit Leader.

This achievement will unlock in Difficulty 4
If Achievement does not unlock rewatch: 1st Unit Leader 1



4.) The Edge of Truth


- Vanquish Dyaus Pita and avenge your comrade.

This achievement will unlock in Difficulty 6
If Achievement does not unlock rewatch: Lindow's will 1 / 2*



5.) Blue Moon

- Thwat Schicksal's ambitions and succeed in preventing the Devouring Apocalypse.

This achievement will unlock in Difficulty 6
If Achievement does not unlock rewatch: God Eaters / Today's Good-bye*



6.) Guardian of the Far East


- Wade into danger to rescue the Far East Branch from its predicament.

This achievement will unlock in Difficulty 7
If Achievement does not unlock rewatch: The Den Under Attack



7.) Don't Run Away From Living


- Confront all hazards head-on and succeed in rescuing your comrades.

This achievement will unlock in Difficulty 10
If Achievement does not unlock rewatch: True Moon in the Welkin / Order Accomplished*


8.) Beacon for Retaliation


- Overcome adversity and succeed in reinstating the 1st Unit.

This achievement will unlock in Difficulty 12
If Achievement does not unlock rewatch: Reinitialization
Credits to: Confu5edPancake

9.) Until We Meet Again

- Unite with your comrades and settle your grudges.

This achievement will unlock in Difficulty 13
If Achievement does not unlock rewatch: Beneath a Blue Moon / Promise*




1.) The Legend Begins


- Collect all trophies.

This will unlock along with your final missing achievement.




2.) Jackpot

- Discover a rare Abandoned God Arc.

This will unlock once you get a rare Abandoned God Arc after a successful mission. Abandoned god arcs will start dropping on Difficulty 4 and is RNG based.



3.) Destroyer

- Break 100 bonds.

You don't have to worry about trying to get this achievement. If you only do the story on your first run, you should be able to get this achievement around Difficulty 5-6. Remember, only aragamis with breakable bonds will count for this achievement, Ogre Tails, Coco Maidens, Zygotes and their fallen variants do not count.

4.) Broken Bond

- Break your first enemy bond.

You'll 100% get this achievement once you do the mission "Kongou Giant" where you fight your first aragami with a breakable bond. Unless you do this mission in multiplayer with someone who is capable of oneshotting the aragami.

In this section I have compiled all the achievements you can get early to mid game. Unlike the Story & Natural Section, the compiled achievements in this section are manually obtained.

1.) Divine Fodder

- Gain strength by devouring an Aragami.

On your very first mission, make sure you successfully perform a devour on the enemy. If you didn't change the settings, a devour is performed by holding Right click or by simultaneously pressing Shift + Right click.












2.) Shared power

- Successfully use a Link Burst.

After a successful devour, you will receive Aragami bullets that can be passed to allies. Upon a successful devour during the first mission with Lindow, Switch to gun form and aim at him then simultaneously press Shift + Right click to administer a Link burst.











3.) Camaraderie

- Teach an ally a new ability.

Once you finish the mission "Devil's tail", The Personal abilities section will unlock. After the mission, just go to Personal abilities > Lindow and teach him "Damage Cut I", that should unlock the achievement once you teach him the new skill.












4.) Exploiting Weakness

- Use a typed attack to devastate an enemy.

After finishing the mission with Lindow, check if you can craft the weapon "Ice Drill" in the Melee section of craft equipment. Craft it and do "Devil's tail" again with Ice Drill equipped.












5.) New Gear

- Craft non-clothing equipment for the first time.

If you did the previous number, you should be able to get this achievement once you craft Ice Drill.




6.) God Arc Tuning

- Upgrade equipment for the first time.

After you finish the mission "Devil's tail", you should have enough materials to upgrade all starter melee weapons. Pick one to upgrade and the achievement should unlock once you do it.












1.) Urgent Mission Accomplished

- Clear an urgent mission for the first time.

Urgent missions are RNG based special missions that you can do. The easiest way to get this achievement is to clear "Mayflies" when you see the message "Mission Available" appear on the top left corner of your screen when you enter the den. If you didn't disable hints in the settings, the game should prompt a tutorial screen once an urgent mission is available for you for the first time.









2.) The Brink of Death

- Perform link aid on an ally.

If an ally's health bar reaches 0, they get incapacitated. You can revive them by sacrificing some of your health. NPC companions rarely get knocked out, if you really want to get this achievement as soon as possible for some reason, just do the mission "Pilgrim" in Difficulty 5 since it increases the chances of someone being knocked out due to the presence of 4 Kongous.










3.) A Power Unleashed

- Activate a Control Unit's effect for the first time.

You'll be able to customize your predator styles after the 6th story mission in Difficulty 3. After you unlock it, go to the terminal then Loadout>Predator styles then unlock and equip any upgrade you wish to a devour. Then, do "Devil's tail" and make sure to perform the devour with the control unit.











4.) Master Predator

- Activate five types of Control Unit effects at the same time.

You can easily get this achievement along with the previous one. Just put different control units on all devours and make sure to perform all of them.













5.) Skill Master

- Activate 25 or more skill effects simultaneously.

This one will eventually unlock if you keep adding Abandoned god arcs to your weapons. To make things faster, craft weapons with multiple effects and put Abandoned god arcs on them. Make sure to optimize your slots and pick Abandoned god arcs that have two or more effects on them. When you think you have enough, you have to go to a mission and beat it.

These are the achievements that you will start to grind for after finishing the story. These will require a lot of patience to get since it will get very repetitive. It will help a lot if you learn about HDH bullets and IOD bullets so you can one shot enemies. (If you want to learn more about these bullets, I made a guide about them here. The guide also includes the bullets I used to grind these achievements.)

1.) Visions of Dread

- Clear a Perilous Challenge mission.

When you finish the story, you'll be able to go on Perilous Challenge missions. Perilous Challenge missions basically make any mission you choose harder depending on what level you set it. You can easily get this achievement by doing "Devil's tail" on any perilous challenge level you desire.











2.) Enigmatic God Eater

- Complete the Challenge Mission that unlocks Ren.

You will unlock this achievement once you successfully beat the Difficulty 14 mission "Anantaboga"













3.) Mysterious Masked Aristocrat

- Complete the Challenge MIssion that unlocks Masked Ogre.

You will unlock this achievement once you successfully beat the Difficulty 14 mission "Watch Out Overhead"













4.) A Real Treasure

- Obtain your first piece of rank 14 equipment.

After you finish the story, you should have atleast one "Generic Compound Core". Use it to upgrade your weapon of choice to rank 14. If you don't have one, refer to the section "Generic Compund Core Farming" section on how to farm for these cores.











5.) Unstoppable Armament

- Obtain a complete set of rank 14 equipment.

You need atleast one rank 14 of each weapon type (all sword, gun, & shield types). There are a couple of ways you could approach this, upgrade the current weapons you have to rank 14 which requires Generic Compound Cores. Or just craft rank 14 weapons* from the crafting section of the weapon types you normally do not use.
Notes:
1.) *The sniper, assault gun and buckler shield do not have any rank 14 versions that can be crafted so you will still need atleast 3 Generic Compound Cores to get them from upgrading.
2.) Since Generic Compound Cores are kind of hard to get, I've decided to create a separate section for it which may help you with farming.
3.) The Hades materials are dropped by the Arius Nova or it can be obtained through material crafting. If you need black tickets, refer to the end section of end game achievements part 2 for a potential way to farm them while racking up mission numbers for the Most Trusted Ally achievement.










(Credits to "Jabberwork" for the help.)

6.) Proud Survivor

- Clear a survival mission on the highest difficulty alone.

The easiest way to get this achievement is to do the Urgent mission Cabin Fever. Each phase only has 1 aragami which should be easier to beat and dodge. Do note that Arius Nova has attacks that inflict venom so prepare Detox Pills/Remedy consumables or equip venom resistance skills.










(Credits to "Maybe a cat" for this idea.)

1.) Elite Unit       2.) Legendary Unit   3.) Most Trusted Ally
1.) Clear 50 Urgent missions.
2.) Clear 100 Urgent missions.
3.) Use one type of equipment for 500 missions.


These three achievements should be the last ones you should do. It takes a lot of time and requires you to be able to one shot aragamis if you want to keep your sanity. I've listed the steps below on how I approached this achievement.

1.) Triggering Urgent Missions & stacking numbers for "Most Trusted Ally"










Doing the Difficulty 14 mission "Grand Prize" atleast 3-4 times 75% always trigger an Urgent mission. Make sure you do the mission solo, so you can gloss through the reward screen faster. Disabling the gameplay setting "Save after mission" is also an option because it skips saving all the time after every mission but remember to save your game before leaving if you ever plan on disabling the option.
If you're a sniper player, Just shoot the Ogre tail with an IOD bullet once(if you have hidden attack and the ogre tail is not facing you) or twice. Average time you can finish the mission is 5-7 seconds .

If you've finally unlocked Elite Unit and Legendary Unit, you can switch to "Watch Out Overhead" if you wish. Just remember that atleast one type of equipment is used for 500 missions. You can check your progress in your avatar card's battle log.










Watch Out Overhead takes only 4 seconds with blast gun, why Grand Prize?
Well, this is also an option for you. If you're only after the achievement then by all means do it. But here are some of the reasons why I think Grand Prize is better:

1.) Easy money

Devour Bonuses from the Ogre tail gives Platinum, Holy Water, and Glowing-eyed Wooden Statue which can be sold for a lot of money.











2.) Black tickets

Also one of the Devour bonuses from the Ogre tail, it might save you some time than farming for the materials you need.











3.) Generic Compound Core

There's a 5% chance this thing will drop from the mission but hey, I think its worth sacrificing atleast 2-3 seconds while grinding for the achievement. From my personal experience, I've gotten 6 of these while I was grinding 500 Missions.











2.) Urgent Missions











I recommend doing survival missions whenever you can. Each phase counts as a single mission so optimize your chances and do a 3 phase survival mission. I recommend "Cabin Fever" since that was the fastest one I can finish.

if you keep doing 3 phase survival missions you should be able to get:
1.) Elite Unit (50 Urgent Missions) - 16 to 17 three phase survival missions.
2.) Legendary Unit (100 Urgent Mission) - 32 to 33 three phase survival missions.

Generic Compound Cores can be obtained from Difficulty 14 to Challenge missions. Most missions have a 20% chance to drop a Generic Compound Core, some 30%. Personally, I farmed these cores through the mission "Beauty's End" which has a 30% chance drop.
Along with that, here are some of the things that will help you raise the chances of getting a core:

1.) Rare Item Rewards Upgrade











If you're willing to sacrifice one upgrade slot, you can craft the "Rare Item Rewards" upgrade which gives another 1% chance to get rare items. It may be small but its better than nothing. Still, It is optional and you should only do it if you are confident enough to sacrifice a slot.

2.) Rare Item For all Personal Ability











Like the "Rare Item Rewards" upgrade, Rare Items For All also gives the same effect for companions. Make sure to form a full party equipped with the Rare Items For All ability when you farm for the cores.

If you do both of the numbers, you will have an additional 4% chance to get the core. Again, Only do this if you're willing to sacrifice slots.

3.) Support skills










Have a support member learn the skill "Reward Rate up IV" & "Support Redraw IV" so you have a higher chance of getting the core and since you'll be playing with a full party, you'll get the chance to re-roll the support skills when Reward Rate up IV isn't showing.

Thank you for reading this guide, and congratulations if you've managed to collect all the achievements for this game. I hope this guide has helped you in any way. I know how hard it is to get the achievements so props to those who really took the time to get all of them.
This section may be a year late but I've always felt like this guide never had a proper closure. But hey, better late than never, please rate and add this guide to your favorites so more people who play this game will see this guide.

If you have any questions or suggestions, feel free to comment it down below or message me about it.

(I saw this at an achievement guide for God Eater 2 Rage Burst so I feel like it'd be for the best to do it here too.)