Mass effect 1: Mass amounts of dialog written for either good, bad or
neutral dialog options. Depending on the option chosen, a whole new set
of dialog choices may be present that the other 2 cannot access. Every
option is also voiced in both Male and Female voices.
Mass Effect 2: Confirmed to have 20+ percent more dialog than Mass
Effect 1. That means 20+ percent more voice overs for both Male and
Female Shepard. Every choice you made in Mass Effect 1 continues
effecting your game in Mass Effect 2, altering the options for dialog
available in the game. If you make a new character in Mass Effect 2
without loading anything from the previous game, your character's
dialog options and consequences will vary from if you had loaded a
previous character, potentially adding or subtracting dialog from the
Mass Effect 3: Since the Mass Effect series has been confirmed as a
trilogy, and it has also been confirmed that your main character from
Mass Effect 1 and 2 may not survive given the choices you make in Mass
Effect 2, that means that a whole new set of dialog will be written for
both Shepard and whatever character takes his/her place if he/she dies
in Mass Effect 2. These two characters will also have to be voiced in
both Male and Female voices who's dialog will be affected by the
choices made in the previous 2 games.
This was written very quickly so if I missed anything, please let me know. Just trying to grasp the mass amount of dialogue that will be in the Mass Effect trilogy.
EDIT: In the original, Shepard had 20 animations for getting into cover. In Mass Effect 2, he has 200. It has also been confirmed that in Mass Effect 2, you will be dynamically talking to characters while behind cover (not just in cut scenes, live fire fight in-game).