The Xbox 360 and PC versions of Fallout 3 include 50 achievements worth a total of 1000 points, while the PlayStation 3 version includes 51 trophies (including the exclusive 51st "Platinum Trophy"). Trophies were not initially available in the PlayStation 3 version. They were added in the 1.10 patch which was released on December 15, 2008.
Every add-on except for Broken Steel adds 4 achievements (totaling 100 points) for PC and Xbox 360 or 4 trophies for PlayStation 3; Broken Steel adds 6 achievements (worth 150 points) or trophies, resulting in a total of 22 additional achievements (worth 550 points) or trophies available with all add-ons.
The image for the "Keys are for Cowards" (pick 50 locks) achievement/trophy shows Vault Boy holding up a lock that has a 100 and not a 50 on it.
Despite both the PC and Xbox having identical achievements, the game has separate IDs on "Games for Windows LIVE" for the two, which makes cross-platform profile comparison impossible.
Saving a game shortly before reaching levels 8, 14, 20 and 30, allows for all level-and-karma related achievements/trophies to be obtainable in a single playthrough. The savegame can then be loaded again, to gain negative/neutral/positive Karma before the level up. One place to do this is Megaton, where one can repeatedly activate Moriarty's terminal for negative Karma, and donate a few hundred caps to the Church of Atom for positive Karma.
On Xbox 360, the acquisition and on-screen notification of trophies may be delayed, from a few seconds to up to several minutes.
On PlayStation 3, the trophy icons for True Mortal and Messiah have been mixed up. True Mortal shows a "Jesus-like" Vault Boy and the Messiah shows the True Mortal icon.
On PlayStation 3, even though add-on trophies are included, gaining all the base game trophies grants the platinum trophy without the need to get the add-on trophies.
On PC, the use of console commands does not block any achievements. This allows cheaters to get all the 72 achievements with the command addachievement <1 to 72>.