Here are the differences I see so far (between this and Veteran difficulty):

- Every enemy has a shield and/or armor you have to wittle down before you can kill them
- There are more enemies in every section
- It takes a lot less shots for you to die (like 3-4 if you aren't shielded)
- I'm not sure, but it seems like there are more Krograns and Vorcha Pyros coming at me.

I don't see how anyone could play Insanity on their first playthrough. I carried over my character that I used to beat the game once, and it's absolutely necessary.
- You get to keep all your weapons and squad points
- You get to keep your level
- You start off with 50,000 of each mineral
- Your allies get to keep their levels and abilities
- You get to choose an additional ability (chosen from whose loyalty you had in the first game). This means you can potential have 2 loyalty bonus abilities.