Awesome game, but it's a shame that it is a bit short.
Pros:
-Ability to customize character
-Storyline is absolutely amazing
-Missions are challenging and fun
-Fun watching how your actions effect others and yourself
-The game has some replayability
Cons:
-Limited ways to respond to questions or characters
-Game is a little on the short side
-The game doesn't really supply enough time to get to know all the characters and locations. Therefore it lets you continue on after the final storyline mission but then it is a bit too late for anyone to have the motivation to finish up loose ends.
-Romances are a bit unrealistic and seem rushed
-The codex is annoying because it contains about 75% of the information immediately at the beginning of the game. Then later there is little more information added to it.
This game is truly enjoyable and worth playing through at least one more time after finishing it, if not more. The missions are quite creative and entertaining since each one is quite different from the last or has a captivating story to it. The graphics are very good, it almost seems like you're watching a movie at times.
I was however dissapointed that the game was pretty short, the only thing that made it last longer was the fact that you could probe planets and find optional missions. The codex is annoying because it dumps about three quarters of the information you need to know on top of you like a school text book reading assignment right off the bat. As much as I want to know about Bioware's Mass Effect world I don't want to read for three or more hours about it when it could easily have been mentioned within the game.
I also hate having things to do after the last mission because the programmers could not coordinate everything to match with the storyline, or because it is too short. After I save the world from destruction, I don't want to have to go back and talk to Legion, because he was obtained just before all hell broke loose and it's time to finish the game.
Please bioware if you're going to put romance options in your games perhaps you should write the dialogue better. It seems there was no effort into any of them. The one with Tali is simply based off of Shepard's past with her. Miranda's is just based off a few suggestive conversations that really have nothing to do with love over lust. Jack is about along the same lines except it's more of a random person on the street asking someone for sex and that person just agreeing to it as if it's nothing.
Overall I'd strongly recommend this game, but some elements could have been tweak a tiny bit, making this game a perfect 10.