Originally Posted by Mykonos

Oh my bloody hell I completely forgot about that one. And the moment on the Derelict Reaper where you have to fight two Scions at once. And the moments where you have to fight Harbinger and Scions at the same time. Okay, I'll revise it:

-Insanity on ME1 isn't too dificult. The trick is to get as much money as you can early on in the game to hit the high mark and get Spectre weaponry. There's a few enemies that are an absolute pain to fight (Armatures take forever to kill) and the cover system's so awful that you have to be quick dispatching the weaker enemies, but as long as you know what you're doing you'll get through with plenty of time.

-ME2's Insanity system is easier in some ways (the lack of shield regen and rock-paper-scissors style barriers means that basic enemies are far simpler to deal with), and combat improvements such as cover in nearly every single battle and more offensive powers mean that with caution it's far easier to win. However, there are those moments where you are doomed to spend hours failing before getting lucky and scraping through a boss fighr with no ammo left. The Praetorians (I actually think the second one's harder because you have to fight more enemies alongside it and there's no circular cover) and select boss fights (the three YMIR mechs in Garrus' loyalty mission spring to mind) provide ridiculously difficult moments to complete. There's also less margin for error with enemies like Harbinger or biotics, as if they manage to get one hit on you, you're good as dead.