- Estimated achievement difficulty: 7/10
- Offline: 47 
- Online: 3 
- Approximate amount of time to 1250: 20-30 hours
- Minimum number of playthroughs needed: 1
- Number of missable achievements: None!
- Glitched achievements: None!
- Do cheats disable achievements?: Yes [In "Keys to the City" Mode]
Crackdown is a great game that unfortunately took the collectibles idea way too far. In addition the cars you must collect there are 800, yes 800, orbs that must be collected for achievements. Other than the collecting achievements, the rest of the list is very fair and sometimes rather fun to do.
Welcome to Crackdown. This game has a total of 50 achievements and requires only one playthrough to get 1250. Of the achievements 9 are unlocked simply by playing through the story and 3 are gained by playing mini-games that are separate from story mode. The remaining 39 achievements are achieved by accomplishing variety of different tasks.
Also, this game has a cooperative game play feature. Although only three achievements require you to play with a partner over LIVE, you can do virtually every achievement with a partner. This will make things go faster for you and also a lot less frustrating. If you don't have anyone on your friends list with this game, you can find a partner in the forums.
Step 1: Preparation
Before beginning your playthrough, it is important to set up your orb collecting checklists. Candied Skull has made a terrific site, HERE, that will answer most of your Crackdown questions. A list of pictures and locations of all orbs can also be found HERE.
Step 2: Play the Game
Note: All progress made through co-op will only be rewarded the to player hosting. All skills and supply points will be saved for the player joining, but story progression will not.
As you play through the game, alone or with a friend, the main thing you need to do is track what orbs you collect. If you don't do this, you will most likely end up with one or two orbs left and have no idea where to look for them.
Step 3: Mop Up
Once you complete the game and watch the ending, you will no longer have to worry about gang members. This is the best time to get all of the achievements that don't require you to kill anyone. Having a buddy in the game with you while you do this will be a tremendous asset.
Step 4: Street Racing, Time Trials and Resurrection
This is the last step. For the street racing achievements, follow the advice posted here. This will make the achievement very quick and easy to get. Next you'll need to beat all the Time Trials on psychotic difficulty. The best advice for this is to have a coop partner. Last, you can resurrect the gangs and go for any of the remaining achievements.
That's it! If you've gotten to this point and followed my advice you should have 1250g. If you're still lost on an achievement, YouTube has a load of videos that you may find helpful.
[XBA would like to thank Method for this Roadmap]