- Estimated achievement difficulty: 7/10
- Offline: 39 
- Online: 0
- Approximate amount of time to 1000: 20-40 hours [Depending on skill]
- Minimum number of playthroughs needed: 2 and multiple playthroughs of single missions
- Number of missable achievements: None!
- Glitched achievements: None!
- Do cheat codes disable achievements: No cheats
- Does difficulty affect achievements: Yes!
Even though this game is a relatively simple 900, the remaining 100 will take some time and skill, which is why it gets a 7 for difficulty.
Welcome to Armored Core 4, a fast-paced Mech action game that will likely take some time to get used to the controls maybe more so than any other game. The game has 39 achievements, which will require a minimum of two complete playthroughs (one on normal and one on hard) with additional single mission playthroughs to get any S ranking you may have missed. 23 of the achievements will be obtained simply by completing both the normal and hard playthroughs; the remaining 16 are achieved by obtaining certain total mission rankings and by defeating certain groups of enemies in the arena.
Step 0.5: Choose your playing style
Prior to begin playing you will have to select one of six ACs, each with different attributes for very different playing styles. Of those six there are three that stand out. There will be a balanced (TYPE-HOGIRE), a fast lightweight with low firepower (SALAF) and a heavy beast (GAN01-SUNSHINE-L) with great offense and defense but with rough mobility. Keep in mind that you can change them as you progress through the game to your liking but for the purpose of preparing for missions that will require great speed and mobility I strongly suggest starting out with the SALAF AC. Not only will you get used to playing with great speed but also this AC is, in my opinion, the easiest to adjust for different types of missions and its original weapons and body pieces are great for the first few missions. Once again, this is my opinion and above all you are suggested to play the game to your liking, but for future achievements I found using the SALAF AC to be the easiest. Also, don’t be put off by when it says that the controls for this AC are difficult because they aren’t. The key in this game is not to sacrifice mobility for defense, since its better to avoid getting hit than being able to take damage. Having an AC with high energy is very important in this game. More energy means: more damage for energy weapons, longer flying time, increased mobility which means a lesser chance of getting a fatal hit; even if you don’t use energy weapons, low energy will not allow you to keep up with enemy ACs in some missions causing you more grief and difficulty that you obviously don’t want. For this I suggest maxing out the following in the FRS: The first 3 from Capacity and either Mobility, Attack or Acquisition) which helps you maintain a lock on of your enemies at high speeds).
Note: Turn Auto Weapon Switch to off. Unwanted weapon switches is the last thing you would want in this game.
Step 1: Normal playthrough
Since you will have to playthrough the game on a harder difficulty, I suggest using this playthrough to get used to the controls and by knocking out all of the arena-related achievements. Since it will be impossible to get an S ranking on many missions with your starting equipment you should concentrate on learning to play and saving your money. As soon as you can, buy a pair of Ogotos for your AC, these are one of the best weapons in the game and will remain useful during both playthroughs and through the S ranking runs. For the Arena related achievements the only weapons you truly need are the Ogotos. As long as you have a high mobility AC with a pair of Ogotos, no one in the arena should give you any trouble. This playthrough should take you around 10-15 hours give or take a few until you are fully in-tune with the controls and the concept of the game. As you progress in the game new arena groups will become available and you should complete them as soon as you unlock them since they give your AC parts that can’t be obtained through missions. By completing this playthrough you should have unlocked the following achievements:
"Chapter 1", "GA Pack-A", "Leone Pack", "Chapter 2", "GA Pack-B", "Aldra Pack", "Chapter 3", "Rosenthal", "Pack Eqbal Pack", "Chapter 4", "Rayleonard", "Pack Maghrib Pack", "Chapter 5", "Akvavit Pack", "Special Pack", "Chapter 6", "BFF Pack-A", "All Data Packs", "Normal Difficulty", "BFF Pack-B"
For a total of 740. Not bad for 1 playthrough.
Step 2: Hard Difficulty.
Now is when it gets interesting, but by now you should be a pro and have nothing to worry about. One or two difficult missions lay ahead but if you make good use of the videos (located on the guide below), The Mission Help Thread and Despised Icon’s schematics and tips for the hard missions you should be okay. For some missions especially the ones that unlock achievements try getting an S rank on your first try because once you do them you won't want to go back for that S rank. Once finished you should have unlocked the following:
"Hard Difficulty", "00-Aretha", "06 Celo", "01 Berlioz", "Ursragna", "02 Sadhana", "Sol Dios", "03 Anjou", "05 Mary Shelley", "25 Borisovich", "14Sherring", "19 Francisca", "--Sus", "10 Menno Ruh","-- Amazigh, 09 Sir Maurescu"
For a total of 200.
Step 3: S ranking mop-up
There are 74 total missions (37 normal, 37 hard) in which you must get an S ranking to obtain your full 1000. You should make use of the video guides and Despised Icon’s Achievement Guide Thread (link) if you are having difficulty with any mission, you can also go to the Mission Help Thread here. After this you should obtain the A, S and SS ranking achievements totaling the remaining 60.
At this point you should have your 1000 or are most likely missing an S ranking on some missions. Remember, patience is key when going for the S ranks, look at the mission requirements for it and find out what you can do to meet them. Even though some seem impossible, none of them are. I’d like to thank Despised Icon for his schematics and mission tips and for a great guide. Good luck!
[XBA would like to thank CienPR for this Roadmap]