Now that i've finished it, i can say my biggest complaint is the story. It had some great moments but overall didn't have the same compelling narrative that the previous titles had. I was expecting so much more of the story of Chief and Cortana to evolve but it felt like 343 barely scratched the surface.
With every previous Halo titles i felt so compelled to play through the story, spending every free minute i had playing, this time there were parts of the campaign that started to feel like a grind to get through.
Thanks to Dirty and Mr Chaotix for the sexy sig