- Estimated achievement difficulty: 5/10
- Offline: 29 
- Online: 0
- Approximate amount of time to 1250: 20-30 hours.
- Minimum number of playthroughs needed: 19 Story Modes, 1~3 Survival Modes, 1 Sugoroku and 1 Mercenary Mode
- Number of missable achievements: None!
- Glitched achievements: None!
- Do cheat codes disable achievements: No cheats
- Does difficulty affect achievements: No!
Don’t be put off by the number of playthroughs required to get the full 1250, the game can be done in the easiest difficulty and the story modes are very short. They can be done with 2 players; you can sit there with whomever you need to finish it with and have your strongest character on the second controller charge at the main boss and tear him/her to shreds.
Welcome to Samurai Warriors 2/XL, created by the famed studios that brought you the Dynasty Warriors series. It’s your basic 1 vs. 1000 scenario that’s in every Warriors game, except that it’s across the sea in Japan. The game with the DLC has 29 achievements, 19 of which can be obtained just by playing most of the characters story modes. The remaining achievements are unlocked after meeting certain requirements in Survival Mode, winning a game of Sugoroku, completing Mercenary Mode and by purchasing certain guides at the shop.
Step 0: Read
Important: Notice that you cannot unlock achievements until after you’ve saved the game; so be sure to save the game right after you’ve unlocked a new character.
Step 1: Story Mode
In order to unlock most of the achievements you will have to beat Story Mode with a total of 13 characters (19 if you’re going to buy the DLC). Some of which will not be available until you’ve beaten another character's story. For example: In order to get the Nobunaga Oda Unlocked achievement you are required to complete Magoichi Saika’s story, but you will not have Saika available until after you’ve beaten Mistuhide Akechi’s story. On the original SW2 you don’t have to play through every character's story to unlock all the achievements, but in the DLC it is required that you complete the new characters’ stories in order to unlock them. Remember to save!
Step 2: Survival Mode
To unlock Ranmaru Mori you must meet specific requirements in Survival Mode, look in the guide below to learn the specifics. Prior to the DLC, the only way of obtaining the Kojiro and Katsie guard achievements was by meeting hard requirements in Survival Mode. But now, if you are planning on buying the DLC, all you have to do is purchase to bodyguards from the shop that are immediately available after installing the DLC. If you are not planning to use the DLC, please read the requirements on the guide below and build up a strong character to the max level in order to make your progress in Survival Mode as easy as possible. I would suggest Iyeasu Tokugawa or Keiji Maeda, since both have great attack power.
Step 3: Sugoroku
In order to unlock Okuni you must win a game of Sugoroku. For a basic guide to the game please read my thread located here. Set the game to a small map and to the smallest amount of gold that has to be reached so you can finish faster.
Step 4: Mercenary Mode [DLC Only]
In order to obtain the two achievements regarding Mercenary Mode you must unite the land under one ruler and make it to level 100 and obtain all of the precious swords. There’s a great guide on Mercenary Mode located here that should answer any of the questions you may have regarding these last two achievements. The secret missions required for the precious swords will be at these stages: 27, 36, 44, 51, 71 and 86. The remaining swords will be offered to you at these stages: 20, 41, 81, 99. Keep these numbers in mind or write them down so you don’t forget.
At this point you should have your 1000~1250, if you're missing anything, double check with the achievement guide and your game to see what you’re missing. The game itself is not hard, just time consuming, which is why it gets a 5 for difficulty instead of anything lower. Just in case, do not download the DLC until you’ve unlocked all the original achievements except for the two guards ones. When you download it, all characters will be unlocked and it may affect the achievements.
[XBA would like to thank CienPR for this Roadmap]