- Estimated achievement difficulty: 3/10
- Offline: 50 
- Online: 0 
- Approximate amount of time to 1000: 15-20 hours
- Minimum number of playthroughs needed: 1, if proper planning is done [see below]
- Number of missable achievements: 24 [Achievements listed as missable in the guide are ones that, if not obtained during game progression, cannot be obtained once the game is completed, during post-story playing, since no New Game+ is available. A new playthrough must be started, or an older save file reloaded]
- Do cheat codes disable achievements? No known cheats
- Does difficulty affect achievements? No [difficulty can be lowered all the way without affecting any achievements]
- Glitchy achievements: No
- Unobtainable achievements? No
- Extra equipment needed? No
South Park: The Stick Of Truth is the long-awaited South Park RPG from Matt Stone and Trey Parker, and developed by Obsidian. The game feels like you're in an episode of South Park from start to finish, not only because of the graphics but also because of the content. So if you're a South Park fan, you will love the layout of this game. Despite the short play-time of the game, there are a ton of collectibles to find and friends to make. The content of the game is hilariously vulgar, and the style of gameplay is that of an old-school, turn-based RPG.
Option 1: Everything in One Playthrough
If you plan everything out before this playthrough, it could potentially be your one and only playthrough for the full gamerscore. To accomplish this, these are the things you need to remember to do throughout your entire playthrough, along with the achievements related to each step:
1. Play as a Jew ("Are We Cool?")
2. Do not sell anything all game ("For The Hoarder")
3. Never end a battle while one of your allies is knocked out. Either revive them before you win the battle, or revert your save and try again. ("No Child Left Behind")
4. Follow the Missable Guide (linked), which details friends, outfits, and Chinpokomon that are missable along the way. Also be sure to follow the Friends Guide provided Here. ("More Popular Than John Lennon", "Chinpokolypse", "Full Arsenal", "Clothes Whore")
5. The following achievements are missable, since they can't be obtained after the story is completed, but can be done many times throughout the game: "Irritable Bowels", "Dragon Wrath", "Re-Buttal", and "Mastery". Be sure to read their descriptions and accomplish them at some point during your playthrough.
6. The following achievements are once-and-done missable achievements that must be acquired at a specific point in the game: "Acceptance", "Heisenberg", "Gingivitis", "Day Walker", "KKK Hero", "Elven Hero", "Perverted", "Too Far", "Truth To Power", "Inside Joke", "Face Hoff", "Outpatient" and "Two Girls, One Stick". Make sure to read their descriptions on how to accomplish them. See the list below on when to do them.
Here I have listed all of the achievements in Step 6 roughly in chronological order of when they're obtainable, along with the area you get them in, as well as the achievements in Step 5 of when the easiest place to get them is.
Acceptance - Kupa Keep right at the start of the game
Heisenberg - Kenny's house during the Calling Banners mission, Tweak's recruitment
Gingivitis - School, first visit (first possible time to get this)
Day Walker - School, first visit
Irritable Bowels - Giggling Donkey, boss fight
Gingivitis - School, second visit (second possible time to get this)
Dragon Wrath - School, second visit (at least 3 opportunities to get this)
KKK Hero - School, second visit
Elven Hero - School, second visit
Perverted - Underpants Gnomes main story quest
Re-Buttal - Underpants Gnomes main story quest (2 battle opportunities to get this)
Too Far - Abortion Clinic
Truth To Power - Cave in Canada (Prime Minister location, who is the only missable person)
Inside Joke - Inside Mr. Slave (must complete his side quest first)
Face Hoff - Final boss battle (must get the nose job before going to Clyde's)
Two Girls, One Stick - Final boss battle
Outpatient - Final boss battle (must acquire Dire AIDS before going to Clyde's)
Option 2: Split Between Two Playthroughs
If you want to sit back and enjoy the game the first time through to avoid spoilers from achievement descriptions and collectible guides, I recommend that at the least, you should do your first playthrough without selling anything for the "For The Hoarder" achievement. That way, on your second playthrough you can sell all the junk and patches you don't want as you progress, allowing you to afford more consumables, making it easier to get No Child Left Behind and to afford all of the outfits from the vendors along the way. If you do sit back and enjoy the first playthrough, and then want to make the second playthrough as easy to get all of the achievements as possible, be sure to check out the suggested class builds Here.
Step 3: Conclusion
No matter how you tackle this game, unless you are constantly searching every room and every area of the game, you'll likely need to use a collectible guide to manage to collect everything the game has to offer without missing something and having to start all over again. Don't let that stop you from enjoying the great game that has been created here. If you're a fan of the series, you should enjoy the immense amount of references and Easter eggs throughout this game, as well as all of the hilarious dialogue throughout.
[XBA would like to thank Necrophage33 for this roadmap]