Assassin's Creed 3 is a really fun game and a nice midway point between the massive world of Black Flag and the relatively contained worlds of Ezio's games.
Personal highlights for me:
They seem like standard side-content missions towards the beginning of the game but this is where you will progress most of Connor's relationship with Achilles and how you will eventually make money. Not only this, but the Homestead missions see you complete missions that seem like more normal tasks. If you ever get tired of killing and maiming, give a go at retrieving a hidden treasure or helping a woodworker recover his tools. It may seem bland, but despite the limited amount of time that gets spent developing these characters, I ended the game caring about the relationships quite a bit.
An extension on the fast travel mechanic from the Ezio games, the Mason Tunnels are a set of tunnels under each city that you can explore at will. You have to travel through these tunnels, solving platforming puzzles, in order to reach the doors leading out into the world. Once you've unlocked a door, you can then fast travel to that point using the tunnel system.
While a utility, the tunnels are entertaining gameplay in their own right, reminding me very much of old-school Prince of Persia platforming puzzles (without the time powers). Definitely one of the better experiences on offer.
This is pretty short. If you've ever wanted to read about the American Revolution from the context of a cynical British man, make sure you read the codex entries and what-not.
Secret Treasure Missions
Often for a cool armour set in Ezio's games, in 3 these missions put you in pursuit of Captain Kidd's treasure. These self contained missions in a small environment have often been some of the strongest points of the Assassin's Creed games and the third iteration is no different.
One of my favourite environments in any video game ever, the Frontier is a massive space, filled with legendary creature hunts, collectables and outposts. You'll complete missions for various clubs, like Frontiersman and Hunting clubs and generally explore a wondrous environment.
Not only this, but the Frontier is displayed in Winter and Summer, completely changing the landscape and the experience. Do yourself a favour and wait til a Summer period to complete any of the missions though! It's much easier!
The weaknesses of Connor are more than made up for in Haytham, one of the more entertaining characters of the entire franchise, Haytham has the same charisma and joking nature as some of the more popular characters from the Ezio titles, such as Ezio himself and Leonardo Da'Vinci.
And my low-lights:
The game is ridiculously buggy, not only are there many gameplay and visual bugs but many missions will fail to even complete. Most buggy are the Delivery Request Citizen Missions. Tasking you with creating a bunch of crafting items (meaning that you need to complete the majority of the Homestead missions to complete these missions) you will often finish collecting the materials but be unable to hand them in. The hand-in NPC will often disappear from the game world or just refuse to take your items. It's frustrating especially considering the hard-work required to get to that point. I've personally experienced bugs with many of the main missions and some Frontier missions.
Encyclopaedia of the Common Man
An on-going homestead mission, this will drive you crazy if you try and do it without a guide, and even then it's pretty frustrating. There's lots of discussions on the internet about the best times and seasons for things to happen so look it up and save yourself the trouble.
Viewpoints no longer reveal the entire map, there will be areas that you must explore on foot still and this is a significant portion of the map, including the Frontier. This is to facilitate the hardest Frontiersman challenges, where you must reveal 90-95% of each map. I have absolutely no idea who at Ubisoft thought this was a good change but it's terrible. Do yourself a favour and write off the Frontiersman Level 3 challenges! :P
"WHERE IS CHARLES LEE?!"
Shut up, Connor...
But yeah, if a lot of my low-points were fixed this would probably be my favourite game in the series but there's enough stand-out moments than mean I end up still really enjoying the experience. I think it's unfortunate really, the game gets a lot of flack, especially with it being stuck between Black Flag and the Ezio series, that are definitely stronger entries in the franchise as a whole. However, the improvement in overall gameplay, when it works, is more than apparent in AC3, especially following on from Revelations, which in my opinion is the weakest game in the franchise.