: Campaign: Bad enemy design
: Bad level design
: Bad writing
: Invisible walls

: Multi: Custom loadouts
: Ordnance
: Armor abilities
: No red Xs
: Bad maps
: Dumb new medals (single kill? Really?)
: Horrible gametype changes
: Imbalanced
: Several custom gametype options were either missing or didn't work

: Both: Worst UI ever. Of all time.
: Sprint
: Slight bloom (on DMR)
: Flinch (as opposed to descope)
: Shitty online stats

: Cut features: Playing as an Elite
: Campaign theater
: Zoom/percision control in forge
: Firefight
: Rendered films
: No screenshots on their website (at launch)
: No in-game file search (at launch)
: Several popular gametypes were cut
: Several emblems were cut

: There's probably a lot more I'm blocking from memory.

What about the art design? Visual retcons galore! The Dawn is a completely new ship. The Chief's armor is a completely new set of armor. The physiology of the Jackals and Grunts was changed radically. And some things just don't look like they belong in Halo. Most of the armor permutations in MP look like they'd be more at home in some tokusatsu series, and have little resemblance to any prior design aesthetic from previous games. 343I's general approach to environmental aesthetics and use of color and lighting is also much different from Bungie's, with many places looking dull and muted, and Forerunner and Covenant creations sometimes looking like nothing seen before.

Oh, and don't forget that they technically retconned the Forerunners from being an offshoot of humanity to being a separate alien species. That makes them less interesting to me.

Since this is a Destiny-focused thread, I will say that I like it overall so far, but it has some major shortcomings, which I will detail in my review. But recently I've wonder if things would have been better if Bungie had stayed on with MS and kept making Halo games.