• Note that this guide INCLUDES SPOILERS!
• It may be discouraging at first, but it is a masterpiece once you grasp what makes the game tick, so don't give up!
• The game doesn't offer any difficulty options; instead, it has a dynamic difficulty that gets harder and harder as you progress through the game, which is a good thing!
• I will be using numpad notations to refer to some moves, mainly the Border Break, so I'll quickly break it down for you:

2 = Down
L = Light Attack
H = Heavy Attack

So if it says 222LH, it means Down, Down, Down, Light Attack, Heavy Attack. All in a quick succession.

There is nothing to say here that hasn't been said already, but it wouldn't hurt to go over them one more time. Note that these tips may not be advanced, as I will be writing down what helped me survive and conquer this masterpiece.

I will not be going over the basic tutorial material, as the game already teaches you what they mean. I'll assume that you're already familiar with the terms I am going to use.

The first thing to keep in mind when dealing with enemies is to never place yourself in the middle of them, as it is very easy to get juggled to death. As soon as they spawn, keep hitting them once and keep dodging until you reach either side of the screen. The main goal here is to make it to the side without getting hit. Once you're there, simply wait for them to come to you and keep doing LL2LL until you've achieved some sort of crowd control, and then simply unleash your EX moves to finish them off quickly.

Even though the game tells you how to execute an EX move, it may be confusing for many people out there. Most of you probably execute EX moves all the time without even realising, and it's perfectly natural! They are simply executed by pressing from L to H in a quick succession. For example, LLLH, LLH, and LH are all EX moves. If done properly, they deplete a certain amount of meter, but there are easy ways to get it back.

Fatal Sync is the state you can enter if the meter is full by pressing its dedicated button, and it is extremely useful if there are many enemies on the screen. What's better is that it allows you to steal HP from enemies, and you can execute as many EX moves as you want! While it could be perfect for crowd control, it's not very useful when it comes to bosses.

There are only 2 hidden techniques, and one of them is quite difficult to pull off, but we'll be heavily relying on Border Break for armored enemies and bosses.

Border Break: 222LH - Requires at least 25% meter to execute and is extremely powerful.
Raging Demon: LL62H268 - Requires full meter, but difficult to execute.

Border Break is literally broken since it makes quick work of most of the bosses and armored enemies, so my suggestion would be practicing until you develop a muscle memory for it so that you can execute it consistently. The fact that it only requires 25% of the meter is wonderful!

Burst can be used to get out of tough situations as well as to punish your enemies. If executed properly, it completely refills the meter!

The most obvious way is to keep killing enemies without relying on EX moves, but it takes a long time. Instead, you can use Burst on an enemy to refill it completely. However, there is one more way that you can regain some of it back, and let me tell you that it is super useful! After executing a Border Break, if you're near any enemy, dashing right after the Border Break animation ends refills at least 25% of the meter. This way, you can spam Border Break and kill armored enemies and bosses quickly!

Well, of course! Not only do they help you build up your combo, but they also break the armor of enemies! You can also switch them with their dedicated button. Be sure to replenish your stock each time you visit the shop!

Red Devil
Enter the Megacity
Story related. Cannot be missed.

Hell of Rising Mists
Clear Zone 1
Story related. Cannot be missed.

Hell of Broken Bodies
Clear Zone 2
Story related. Cannot be missed.

Hell of Many Colors
Clear Zone 3
Story related. Cannot be missed.

Hell of a Hundred Devils
Clear Zone 4
Story related. Cannot be missed.

Hell of Iron
Clear Zone 5
Story related. Cannot be missed.

Heaven above Hells
Clear Zone 6
Story related. Cannot be missed.

GENERAL HERCULES J. THORMAN
Defeat The Iron General, Hercules J. Thorman – First of the Five Calamities
Story related. Cannot be missed.

Beloved by the Bullet
Defeat Enyo – Second of the Five Calamities
Story related. Cannot be missed.

The Fire From Heaven
Defeat Uriel – Third of the Five Calamities
Story related. Cannot be missed.

Hell's Own Judge
Defeat Regent Wuguan – Fourth of the Five Calamities
Story related. Cannot be missed.

Our Body
Overcome your ally
Story related. Cannot be missed.

Love Always Remains
Overcome your lover
Story related. Cannot be missed.

Mortal
Overcome your enemy
Story related. Cannot be missed.

Shou Time
Get an 'S' rating
Self-explanatory. The first few levels are very easy to get an S rank. You'll naturally get this on your first playthrough. If you can't, check the description of the achievement below.

Chosen Executioner
Clear all levels with an 'S' rating
This is a very difficult achievement to get, but it's doable with enough determination. Keep in mind that you don't have to kill every single enemy on the levels. There are only a few encounters that affect the overall score, and your goal should be avoiding damage and keeping your combo high. This playlist by i9riser is a great guide on how to get S rank from every single level. Keep in mind that the SovKhan fight doesn't count for the achievement.

God Speed
Complete the game in one sitting under two hours
This is way easier than it sounds if you've already got S rank from all levels. You have to start from Intro, not 1-1, through Level Select and play to the end, beating the game under two hours. You can even die a few times!

Getting into Knives
Bomb, rope, lamp oil, you got it!
It pops up after you purchase all munition upgrades. Don't worry about the money, you'll have enough. You'll probably unlock this before 3-1 on your S rank run.

Absolute Sync
Fully upgrade Shou's attributes
It pops up after you purchase all upgrades for Shou. Don't worry about the money, you'll have enough. You'll probably unlock this before 3-1 on your S rank run.

Dark Historian
Unlock all lore
There are golden troopers on each level that you need to kill to unlock a new lore entry. This video by i9riser is a great guide on how to locate them all.

You want it?
Browse the shop
Self-explanatory.

Our Finest Customer
Shop till you drop (dead)
The conditions are unclear, but I believe you need to buy a few things from the shop for it to pop up. It triggered when I bought a few upgrades and munitions from the shop.

Spectacle
Achieve a 20-hit combo
Self-explanatory. It's quite easy, but if you're struggling with it, then gather a few enemies and throw a few bombs at them. Preferably the second or the third munition choice.

Fatal Sync
Achieve a 50-hit combo
The same thing applies to this achievement, too. Be sure to be in Fatal Sync state to have a better chance!

Sword Saint
Parry 30 attacks
Parrying is inconsistent due to its questionable input, and I've never used it willingly. You'll get this naturally.

How the sausage is made
Turn 20 enemies into a fine red mist
You have to gib your enemies for this to pop up, and if you've been using EX attacks to finish them off, you'll get this naturally. LLH or LLLH is a good way to gib them.

Hit the tatami mats
Enter the training room
Self-explanatory. Just enter the training room for it to pop up.

Forbidden Knowledge
Discover a hidden technique
You need to perform either Border Break or Raging Demon. 222LH, baby!

Promotion Denied
Deny a man his well earned pay raise
On 1-2, you'll face your first mini boss. Just parry his bullet. It's always the first attack he does.

Hollow imitation
Overcome Atavaka
You have to defeat Atavaka when you first encounter him on 1-3. If you have all upgrades and mastered the Border Break, then you'll have no problems with it. Be sure to throw a few munitions, too!

Ball is Life
Make a free-throw!
At the very beginning of 2-3, you need to throw a bomb into the hoop behind you.

I like clubs
Get down in the disco
On 3-3, you'll come across a disco that plays the remix of Beebop140 from the original Slave Zero. It popped up for me after doing a Border Break in that section.

'Friendly' Fire
Unknowingly committed Fratricide
This achievement is bugged. At the end of the 3-3, after Enyo destroys the Church of SovKhan, you'll be surrounded by troopers. Among them are troopers with yellow rifles. Make Enyo kill them. Since it's bugged, it popped up for me after entering Fatal Sync during that section. Enyo wasn't even shooting anyone, but she killed quite a few before that.

Spell capture failed!
Time out Devil's Precipitation
During the first phase of the SovKhan fight, he'll start casting a huge skull after taking enough damage, and you need to hit him to cancel the spell, but instead of hitting him, just stand there and let him do his thing.

Both halves of hope
View all story scenes
This is actually missable if you skip any cutscenes or dialogue. Don't skip anything, and it will pop up before the credits.

Crimson Citadel is a mode that is pretty much like Bloody Palace from the Devil May Cry series, but shorter and easier. You may have already noticed that after doing everything, two palettes remain locked, and to unlock them, you simply need to beat the Crimson Citadel. One of them unlocks halfway through the run, and the other one requires you to finish it.

Here's a video of me playing the Crimson Citadel, plus some extras. It's nothing exceptional, but I make use of all the tips I have given you above.

Also, after finishing the Crimson Citadel, a new boss fight unlocks: 300% SovKhan. Good luck with it. Try not to cheese him with Border Break!