- Estimated achievement difficulty: 8/10
- Offline: 21 
- Online: 4 
- Approximate amount of time to 905: 45+ hours
- Minimum number of playthroughs needed: 1 [2 recommended]
- Number of missable achievements: 0
- Do cheat codes disable achievements: No cheats
- Does difficulty affect achievements: Yes
- Glitchy achievements: None
- Unobtainable achievements: Yes ["Tournament Qualifier", "Gotham Hero", "Gotham TV Sports Fan"]
- Extra equipment needed: A second controller is recommended.
NOTE: Gotham TV and the tournaments have stopped running, so if you don't have the related achievements already you can only obtain a maximum of 905 from this game
This game is probably one of the harder games out there for getting the full 1000 achievement points on, however a majority can be done without too much time and effort. There are currently no known glitched or missable achievements however the tournaments that are run are usually country dependant, i.e only players from certain countries can enter them. Since this is the case then this achievement may be unobtainable for some as there may be no tournaments ran in their country.
Step 1 - Career mode:
The first thing you'll want to do is career mode. I recommend starting on silver because at the beginning, you only have basic cars which are extremely difficult to use to complete the game with on the harder difficulty levels.
At the start, I also recommend buying the Ariel Atom. While progressing through the game you'll earn a considerable amount of credits, it is recommended that you save these until you can afford one of the games top cars such as the Ferrari F50GT or the McLaren F1, this should give you the advantage later in the game.
Step 2 - Career mode on platinum:
After your fist play through, you'll want to do the game again on platinum. This could take a very long time depending on your skill and requires a lot of determination. Most of the races are fairly easy but the hotlap's, time trials and cone challenges are not. For hot laps and time trials, you will need to learn the fastest route through every corner and keep pushing until you beat the time (if you can't do some of them, changing to a car of a lower class increases the amount of time you have to do the lap and as such may be easier). For cone challenges, you'll need to know the location of every set of cones and to know how to slide the car so you never lose your combo in between the sets of cones.
Step 3 - Online:
Due to the fact that this game is rarely played online anymore, it will probably require you to boost the online achievements with a group of players. To find some, go visit the forums. While some of you are boosting in online career mode, the rest of you should be watching them race on Gotham TV as well.
Next you need to qualify for a tournament. Tournaments are still ran weekly however it is not known how much longer that this will be the case. Also, different countries have different tournaments so depending on your country this may be unobtainable altogether. Furthermore, tournaments still require a lot of skill to qualify for them. It is recommended that the day before the tournament qualification ends is when you should try to qualify, as this will ensure that you don’t get kicked out of the qualification zone. Also make sure that you turn up for your allotted time slot because even if you qualify, you’ll miss out on the achievement.
Finally, the achievements that require you to do events in modes such as cat & mouse and cone capture are easiest when boosted with friends online. However these four can also be done offline using a second controller in necessary.
Step 4 - Finishing up:
By now you should have enough credits to buy all the cars needed for the Lamborghini, Ferrari and Exotic car club achievements. If not the last race in career mode on gold gets you a lot of credits and can be done repeatedly until you earn enough for them. Next you should go for the "Race Against the Clock" achievement. All you have to do is set a lap time on every track. Once you have set a lap time (even if you crashed mid way around and it wasn’t good) there is no need to do another faster one.
Also you may be missing the style racer achievement. The description of this can be confusing. When it says "kudos for every maneuver" it means in a single race and this can be quite hard to do. There are several methods of getting it and a quick search on a popular search engine will reveal some in depth guides for this achievement (Note: you don't need kudos for cone gate as this is obviously not obtainable when in a regular race).
Finally you should wrap up any other achievements you have left, see the achievement guide for more details.
At this point, you should have all achievements in the game. If you can't seem to find any tournament being run for your country, just keep checking back regularly. If there isn't one after a few weeks when you've been checking every day, then there's a good chance there won't be anymore and the achievement will become unobtainable.
[XBA would like to thank Caramel Cardinal for this Roadmap]