I really enjoyed this game, i wasn't expecting to after failing to finish 3, but it kept me entertained. The main protagonist, Edward, is far more appealing than the previous one. This game may be the buggiest game to date that i've played in the series, not going one memory without a notable glitch, but nothing a reload couldn't fix. Another personal issue with the game, more than half of the game is spent solely as a pirate, that's all i can say without spoiling it. I just wish you spent more time as an assassin.
Sidenote: the combat is undeniably harder than previous versions, the lack of a lock-on mechanic, in an attempt to simplify the fighting, really seemed to detract from the game's functionality. There are enough collectibles to keep you looking for hours, yet the reward for completing the list is almost nonexistant, and not worth your time. Ship Battles were unexpectedly one of my favorite aspects of this game, while maneuvering the large ships might seem annoying in some tight areas, out on the open sea targeting an unsuspecting high level ship filled me with the best kind of mischievous excitement. If you're a fan of the series and you're genuinely interested in the story, i'd say it wouldn't be a bad idea to rent it out.
I have been a fan of Assassins Creed since its debut and will always be a fan of it. While I did find some aspects of the game enjoyable such as being a pirate, dive puzzles, and ship battles and some other things.
Overall I find the game far too easy. Almost right out of the gate you can invest in upgrading your character's weapons and ships stats to the max. Feels like they hardly put any effort into the hand to hand weapon system. One thing that really bugs me is that they immediately give you the locations of almost all of the collectibles (by synchronizing a way point) making it feel like one big grindfest.
All in all I can't say this was my favorite installment of this game but it does has its pro's too and is worth playing.
If you were losing/lost hope in the AC series, this game will redeem them. This honestly proves yearly released games don't have to seem rushed together.
Pro: -The main character is a fresh start for the series, acting like a real pirate (No "arggh"s, so don't expect them).
-Sailing the open seas and hunting are well put together. It makes pirating look easy.
-Being an assassin seems like something Edward does by habit, not by conviction.
Cons: -Occasionally the graphics can get a little choppy
-Similar free-running issues from previous games, but not NEARLY as bad
Overall, get this one. It's definitely worth your time and effort and has a lot to do once you get started.