A recent issue of Game Informer magazine has unveiled the first details on Mass Effect 3, the upcoming conclusion to BioWare's Mass Effect trilogy. A lot of the information may be considered a spoiler for the game's prologue, but many of the gameplay details are quite revealing.
The first thing that needs to be mentioned is that Mass Effect 3 will be bringing back some degree of the more complex character customization that was simplified in Mass Effect 2. Characters will have more complex skill trees, and the system of "evolving" powers will be expanded so that powers can be evolved multiple times. Classes will not be as limited in weapon selection as before, since now any class can use any weapon, though classes are limited in how many weapons they can carry. In addition, weapons can now be modified and customized with parts like scopes and barrels, and these modifications will affect the appearance of the weapon.
The issue also addresses the question of which characters from the previous games will be playable in Mass Effect 3. So far, Liara, Garrus, Ashley, and Kaiden have been confirmed as playable, assuming that they survived the previous games. Other characters, including Wrex, Mordin, Legion, and Anderson, will appear in the game, but will not join Commander Shepard's team. The Illusive Man, Shepard's patron in Mass Effect 2, will also return, though it appears that his organization Cerberus will be returning to a more villainous role in the game.
As mentioned above, the rest of this information will contain spoilers for the first few minutes of the game's story. The game begins with Commander Shepard on Earth because he (or she) has been put on trial for the events of the Mass Effect 2 "The Arrival" DLC. This trial is interrupted by the sudden invasion of the Reapers, and Shepard is forced to flee Earth in order to gather forces to defeat the Reaper threat and save humanity. There will be multiple alternative endings for the game depending on how Shepard goes about this task.