Originally Posted by jhns
If you play the first one, you can use your character in the second. The story and characters you run into will be different depending on what you do in the first. I haven't played enough to figure out how different it is. You will also get more of the storyline if you play through the first one as the trillogy is one long story.
If you don't care about missing some of the story, they do explain what is going on so you don't have to play the first. If you really want to catch up, you get a codec that has audio clips that will tell you everything. Also, even if you use your ME1 character, you still start at level 0 and don't have any upgrades.
So, in short, you don't have to play the first to play the second but you will get more out of it if you do. It is also interesting to see how much they changed it. This one is a very different experience from the first. They changed a lot.
You get bonuses for levels and RICH achievement though that carry over, also you start at higher levels based on where the playthru you loaded finished. a 60 starts at lvl 5 with 100,000 creds, and like 10,000 resources.
over 100 choices carry over too.