I have just completed my first play through of Mass Effect playing as a soldier. All I can say is I was blown away.
I have played tons of RPGs (Role Playing Games and not Rocket Propelled Grenades) and I can safely say that Mass Effect takes a piece of the pie. Aside from the gamplay there are several elements which made this game on of the best that I have ever played.
The story drives the game. It follows the same formula as many other scripts but the way that the elements are melded together with the interactions of the characters allows the game stand out.
The cinematics can only be described as excellent. The gameplay and in-game movies flowed together was so natural that it felt as thought there was no difference between the two of them.
The mini-games or puzzles as young gamers call them were interesting and fun to play. They were not difficult to the point where I had to pull my hair out because I could not solve them or had to play them over a half dozen times to solve them like in some of the other games that I have had the unfortunate luck of playing.
Many of the choices that we must make in the game really does matter in the long run since they will have unforeseen outcomes that will affect the story.
Finally, the music score. The choice of music was tastefully chosen. The music sets the mood and complements the visuals and the part of the story that the player happen to be playing. I found use of horned instruments in parts of the story definitely conveys the hero effect on the player.
I am on my second play-through now playing as an Infiltrator.