I'm not using a different hard drive. It's the SAME drive, on a new machine. I had an old Xbox with 20gb hard drive, played half of Gears, bought a new Xbox, moved the old 20gb drive to the new box, resumed my old Gears campaign, and didn't get the achievement. I did in fact play the first half of the campaign offline on my old box (didn't have Live at the time), I just thought that, when I put the drive into a new box and activated Live, I'd get credit. And I did not.

Oh well, water under the bridge at this point. I went back, replayed the first part of the game, and got credit. All is well, I just don't understand what happened.

Oh, and as to Gears 2 on Insane, it's really not that bad. The overall level of difficulty is higher than Insane mode in Gears 1, but there are nowhere near as many frustrating points. I remember the part at the end with the Reavers, for example (Gears 1), being practically a crapshoot. Get on the turret and start blasting away. Sometimes you'd get instantly vaporized, sometimes you'd get through, with no noticeable difference in performance on your part. Gears 2's Insane mode is much more fair. There are a LOT of battles that will take a few tries to get through, but very few that you'll get stuck on, and almost none that are overly annoying.