Overview
-Estimated achievement difficulty: 3/10
-Offline: 50 (1000)
-Online: 0
-Approximate amount of time to 1000: 9-10 Hours
-Minimum number of playthroughs needed: 1+ (some mission replays and challenges)
-Number of missable achievements: None (missions select)
-Do cheat codes disable achievements? No cheats (Costume unlock codes are okay)
-Does difficulty affect achievements? Yes, but difficulty achievements stack and on new game plus you can pick hardest difficulty, and just replay last mission for achievement).
-Glitchy achievements? Some achievements may take a while longer to unlock, specifically kill based ones.
-Unobtainable achievements? None
-Extra equipment needed? No
Introduction
You get to pick 1 of the 3 characters available from the start of the game. You can pick any one you want, none have specific achievements related to them. You can pick any power you want, again no specific achievements related. The difficulty can be whatever you want as well, though there are achievements related to difficulty. You can play through on the hardest and all difficulty achievements will stack. You can, however, just start a new game+ from an easy playthrough(continue after beating game) and select the hardest difficulty. Replay the last mission, and the achievements will unlock for the harder difficulties. There are collectibles in this game in the form of challenges, posters, dossiers, and X-Genes. Follow the Collectible Guide HERE to reference where they are at. Just to point out, you do not need 100% of the suits and X-Genes for any achievements. You only need one entire set for an achievement.
Step 1: Brotherhood playthrough on easiest difficulty
This game has a system set like many other games, where your choices make you on one side or another (good/bad, light/dark, etc). The actual status bar has literally no effect on any achievements, so do no pay attention to it. Pick the easiest difficulty and as you play through, always side/choose anything to do with the Brotherhood. The characters in the Brotherhood include Magneto, Mystique, Toad, Pyro, Quicksilver, and Juggernaut. Make sure to always side with them. There is no need to ever dashboard to pick an alternate side for an achievement, it is not worth it.
You will get all collectible based achievements as well as 14/15 challenges. You will be missing Northstar's challenge. When you speak with him in the game, he will talk about his challenge but it will never trigger. Ignore this and move on.
Step 2: Replay specific missions for alternate achievements and challenge
Now you need to replay the specific missions below. They will allow you to get the remainder story based achievements as well as the last challenge. Go to load game in order to replay a level.
Mission 2: Pick to help Nightcrawler. Later on in the level, pick to Go with Cyclops. After you get both achievements associated with those choices, you may quit back to the main menu.
Mission 5: This mission sets you up for getting Northstar's challenge. You must get to the end of the level where Nightcrawler is. He will ask you where you want him to teleport. This time, choose the X-Men.
Mission 6: Now play until you get to to Northstar and you can finally do his challenge, which is the last one you need. Continue on with the mission and fight Magneto and Juggernaut again. When asked who you want to go with, pick Cyclops and the X-Men. This will give you an achievement as well as set you up for another achievement in Mission 7.
Mission 7: Last but not least, play until you have to destroy the 4 devices to save Northstar from mind control. Once done, you will get your last story based achievement.
Step 3: Replay Challenges/Mop Up
Note: The reason this is not the last step, is because once you start a new game on the hardest difficulty you will be playing the challenges on that difficulty. It's true you can change your difficulty in game, but you would have to do this every challenge.
Pick the various challenges that you failed to complete. Once they are done, get your kill achievements. Refer to "The Goon Squad" achievement description in the guide for more details and help. You can also replay levels to grab any collectibles you may need.
Step 4: X-treme and X-Man difficulty achievements
From the main menu, choose continue. The game will tell you about how you will keep your stats but your non-important status with X-Men and Brotherhood will be cleared. Accept the terms, and this time choose X-treme difficulty. Once the game starts, quit out to the main menu. Go to load and pick your character. Choose to play on Mission 8. This will be the hardest part of the game, you may look at the associated difficulty achievements for more info. After beating the last boss, you will get both achievements since they stack. Now you can reload the mission and let yourself die up to 100 times to get your 0 pointer.
Conclusion
This is a pretty short game in general and very easy on the achievements. Not being able to skip cutscenes makes this game longer than it normally would have been. Also, with 3 characters, 3 different power type trees, and 3 different power choices, you could still put a lot more time into this game. If they had achievements based on playing as every character and every power type, this game would have been twice as long at minimum. Seems they give you 1000 points and you only get to experience 1/3 of the game.
[x360a would like to thank Tyger7 for this Roadmap]