To review a Peter Molyneux game without mentioning his penchant for outlandish promises and how the game in question doesn't live up to them is heresy. Thankfully, Mr. Molyneux' promises were relatively benign this time around, focusing mainly on gameplay aspects and most of them came true.
Fable II continues in the same world (Albion) as Fable I, only several hundred years later, leaving the swords & sorcery Medieval setting behind for a more 18th century feel. This makes for a slightly more original setting and is still done in the traditional irreverent Bullfrog/Lionhead style.
The main quest and storyline is much improved over the original Fable and while not particularly longer in gameplay time, it provides a far more interesting set of characters, a personal favorite of mine was Reaver voiced by the ever enjoyable Stephen Fry, a real bastard of a rogue.
Decisions you make during your quests have far more impact on the world, due to several points in the storyline where time advances in big leaps, allowing you to see the long-term consequences of your choices. This is a huge advancement over Fable I, where the only real indicator of your morality was your character.
The dog was often mentioned by Peter Molyneux and it is a great addition to the game. While the dog does not offer much gameplay opportunities (besides the fact that it find treasures for you and sometimes bites enemies that are downed) it provides an emotional anchor to the game. While your character is not allowed to express much beyond the emotes you gather, the dog is a mirror for the player. It gets scared when it enters a dungeon, it growls at enemies. The excellent animations of the dog makes it come alive and feel like an actual living entity, not unlike the creatures of Black & White.
The combat, which was much maligned due to it being one-button only, is not bad. There is an element of timing required to land combos and the feedback of a strike is very satisfying, both in the animations and audio. There are three types of attacks you can do: Melee, Ranged and Will (magic). These are all mapped to three of the face buttons, allowing you to switch between types very quickly.
Fable II is obviously a Lionhead game and so it suffers from the same faults all the other Lionhead games have. In my opinion there are two major downsides to every Lionhead game:
1. The interfaces are terrible. I'm mostly referring to the menu structure here. In Fable II for example, to change your currently equipped melee weapon you need to dive down three levels of nested slow-loading, overly animated menus. Also targeting of a single peasant who has a present for you in the mob of people following you when you have a good disposition is troublesome.
2. You are largely responsible for making your own fun. The fun in Black & White wasn't doing the missions, it was teaching your creature to eat his own feces. The fun in The Movies wasn't running a successful business, it was creating the movies. In Fable II you can breeze through the main quest very quickly. You'll get more enjoyment out of it if you do the ancillary activities like marriage, working jobs and exploring the world. However, this is never really explicitly encouraged by the game, other than not pressuring you to immediately go to the next strand of the main quest. So if you are the kind of person who does not stray from the path the game shows you, you might end up a bit disappointed by Fable II.
Overall Fable II is an excellent linear RPG that provides enough entertainment for those who are willing to seek it out.