-Estimated achievement difficulty: 7/10
-Offline: 39 (770 )
-Online: 11 (230 )
-Approximate amount of time to 1000 : 45-50 Hrs
-Minimum number of playthroughs needed: 4
-Number of missable achievements: No. You can replay chapters.
-Do cheat codes disable achievements? No cheats. People have found glitches to farm resources.
-Does difficulty affect achievements? Yes (certain modes are automatically put on hard difficulty).
-Glitchy achievements: None
-Unobtainable achievements? None
-Extra equipment needed? No. Kinect Enabled Voice Commands are optional. They are simple phrases you can use to find objectives, access inventory, etc. Press , go to settings, and then to Kinect Commands to find out what they are. If you really want, you can buy digital content with real money. If you want weapons or even resources, you can purchase them with real money.
-Online Pass Required?: Yes
You can start the game on any difficulty you want. You must complete it once to unlock other modes. You will need to make sure you gain all of the various collectibles, as there are quite a lot. The nice thing about this game is you can hit whenever you want and see what collectibles you need in that specific level, or even look at the achievements section which tracks the stats needed to unlock them. You can do this from the main menu too. This game does have co-op and you will need someone to play with in order to gain certain achievements. This is drop in drop out type, so you can have people help you in certain situations if needed. You will need a co-op partner for certain side missions which have their own collectibles in them too. The game does not save your stats if you die. You cannot just keep getting a headshot on a soldier for example, and then let yourself die to repeat gaining stats on the same enemy. You must hit a checkpoint while you move on for the stats to save. The game has 19 chapters that you must complete. You can replay them if you want from the main menu, so it will be easy to grab collectibles if you missed a few. Make sure you always save and quit.
Note: When you start different modes, you will get a separate save file for them. You will not overwrite your existing save.
Collectibles: These do not carry over from save to save. You will have to do these in one playthrough. Do this on your first playthrough on normal mode (casual is best to make it easier for you).
Playthrough 1: Any difficulty
You can tackle your first playthrough however you'd like. Easy and with a co-op partner? Your choice. Impossible by yourself? Good luck. I advise you just take the easy route and destroy everything in your path while gaining all collectibles and doing all side missions. You'll have three more playthroughs to provide "challenge" if that's what you seek.
Playthrough 2: Classic
This is automatically on Hard Mode. You can only use weapons from blueprints. Aiming is slightly different. This is supposed to be like Dead Space 1's way of doing things. You cannot play this mode in Co-Op. If you happen to have DLC weapons, they do carry over (like the limited edition ones). If you have them, this makes this mode a lot easier! Also, this is a different save file. Your collectibles won't stack, and you will not have any of the resources you earned from the previous game.
Devil Horns: You will earn this weapon after beating classic mode. It's basically one shot kills and has a ton of ammo (it would be hard to run out). To play using this on Pure Survival, you will need to delete your cache and play offline so that you get the blueprints on your save file. Afterwards you can update and start playing online again.
Playthrough 3: Pure Survival
This is automatically on Hard Mode. You do not get drops from enemies in the form of ammo and health. You must craft all your own stuff. You can play this in Co-Op mode. Using the "trick" above about Devil Horns will make this an extremely easy playthrough since you will not have to worry about ammo as much and will kill things in a single shot. Normally in other modes, during the first chapter you will see an offline bench. In this specific playthrough, it is online and you can get the weapon from the safe. If you have a friend in the game it helps a lot, especially if they also have the Devil Horns. This should be your quickest playthrough.
Playthrough 4: Hardcore
This is automatically on Hard Mode. If you die, you will start your whole game over. You can quit out and have checkpoints like normal, but a death will reset you. You can make this easy by just having a backup save on your USB or Cloud. Keep switching the saves around and if you die, load the one that isn't at the start of the game and make a copy of it. Continue this route until you beat the game. Not as tough as Dead Space 2. Having the Devil Horns will really help you out here.
There are a few side missions that have collectibles that you must have an online partner to complete. There are also a few "partner" related achievements you must gain as well. Check the guide for the details, but they are very straight forward. A word of warning, when playing in Co-Op a lot of times you will lose certain achievement progress after quitting out. Gaining certain types of kills may vanish next time you start up. The save system is not very forgiving.
Having to play the game four times with variations of difficulty in each mode can create some worry. The fact that there are well over 200 collectibles will also discourage some. Most of the collectibles are extremely easy to find and following a guide will make it much easier. Chapter select and drop in Co-Op is a very nice addition to this game. The best advice is to play all four playthroughs back to back. This will give you a huge advantage by the time you hit hardcore because you will be very familiar with everything.
-Estimated achievement difficulty: 1/10 (With Devil Horns) 5/10 (Without)
-Offline: 7 (230 )
-Online: 1 (20 )
-Approximate amount of time to 250 : 1-2 Hours
-Minimum number of playthroughs needed: 1
-Number of missable achievements: No (You can replay chapters)
-Do cheat codes disable achievements? No cheats.
-Does difficulty affect achievements? No, but must play on Pure Survival mode.
-Glitchy achievements: None
-Unobtainable achievements? None. Though if you have never completed Dead Space 3, you will not be able to choose the Pure Survival mode.
-Extra equipment needed? No.
-Online Pass Required?: Yes
WARNING ABOUT COLLECTIBLES:
If you start this game on any of your save files and have not yet obtained the achievement for collecting everything, the collectibles from the DLC will be implemented as well. This means you would have to then also collect all parts, logs, etc in the DLC as well as the main game.
[XBA would like to thank Tyger7 for this road map]