I completed yet another Halo 2 chapter tonight (four left to go, I think), but after getting the achievement it then told me “Sorry, Please insert the original Halo 2 disc”, even though I thought the activation scheme isn’t supposed to need the disc post-install. Then it dumped me back to the main menu, and when I tried to resume the campaign, it told me that I had an “invalid checkpoint” that did not match the one on XBox Live, and I could either restart the level or continue without achievements. No matter which one I picked, it dumped me back at the start of the chapter I just finished, though. Ugh.
Fortunately, I discovered that I can go back to the main menu, reselect the character profile, and then use the ‘start a level’ option instead of ‘resume the campaign’, and then I can choose the next level. It had me worried for a bit there, though.
As for this last chapter, there was tons of vehicle-piloting, including my favourite, the Scorpion. At one point it wanted me to board an ally’s much weaker vehicle and he’d take me to the next area, but screw that — I stayed on board just long enough to trigger his movement there, and then jumped off and ran back to get another Scorpion again. It only takes two or three shots from its cannon to take down the larger Librarians, instead of the multiple clips of conventional weaponry.
At the end was yet another elevator ride where me and my allies were attacked by waves of Flood. I kept dying a lot as groups of them overwhelmed me, but soon discovered that I could stick to one spot and I’d only have to deal with them one or two at a time, which was easy with a Plasma Sword.