Singularly dull game. Also, very difficult to figure out where to go. Often, waypoint markers did not show up. The ending sequence, I had to play two dozen times or more to pass.
Upon replaying this (nine years after the first time), I was stunned by how short the game was. Less than six hours altogether, but it took about 12 hours the first time through. Probably part of that is the difference between playing with keyboard and mouse now vs. gamepad then, but it's still astounding.
That aside, my opinion is pretty much the same. Not a very interesting game, annoying ending sequence. The bits with Cortana showing up and the game slowing down weren't dramatic, just irritating. I died quite a few times, but almost all of those were one-hit kills from snipers or similar. Probably there's a way to play it safe and prevent that from happening, but it's not interesting enough to make me want to do that better.