Other than the removal of tanks, flamethrowers, any other fun weapons (and a generally reduced arsenal), planes, skydiving, vigilante missions, taxi missions, ambulance missions, firefighting missions, buying and owning property, managing businesses, real exploration rewards, diversity of environments, diversity of missions, creating and improving gangs, conquering territory, advanced character customization, eating, jetpacks, the military, a good attack helicopter, the attack plane, custom cars, custom radio station, and anything remotely resembling wit in the humor, it's a great game and the best GTA game.
If you do happen to miss that stuff (much of which was even in GTAIII), then it's the worst GTA game ever made, and a steaming piece of shit that shouldn't be rated above a 7 because all it is now is a mediocre shooter game that doesn't remotely possess any of the features that made GTA an enjoyable franchise in the past.
Of course, if you're brain can't register deeper thoughts than "oooh purty graphics and stuff goes boom" then you probably didn't notice any of these missing features, think it's a great game, and have a job in our review industry.
