What an odyssey this was (see what i did there). I played on nightmare, did every single quest, did every single location on the map, got all achievements and it took me 155 hours.
The good
I haven't liked and i mean really liked the cast of side characters in AC games since the Ezio trilogy, but this game is an exception with the abundance of well written and well acted characters that you either meet during most of the game or 1-2 times during the whole game. They have really stepped up their game in this department and i'm really happy i actually get characters i get attached to, not like the forced attachment from previous AC games (looking at you Black Flag with that annoying flashback that wanted me to cry about those who died while i forgot most of their names).
I liked the powers and the whole RPG upgrade tree of this game, but it still had it's flaws. Having the tree unlocks tied with the spear upgrades and those upgrades being tied to the cult of kosmos is kinda bad design especially if you want to kill them as fast as possible you are kinda robbing yourself of the pleasure of actually playing the game not just rushing to the next cultist to upgrade your spear so you can have fun with the enemies. But wait, if you do that then you most definitely will be towards the end of the game. Then when are you actually going to have fun?
I really liked the recreation of greek cities, they made me feel like i was going back in time.
The main story was really well done and i enjoyed my time with it. I tried and succeeded in reuniting the family at the end of the main quest line. Haven't liked a main quest line this much since the Ezio trilogy.
The bad
Real money item shop in a single player game.
The map is way too big and filled with too much filler content for my liking. Even tho i did everything on the map it took me 150+ hours over almost half an year of playing on and off because of the brain dead activities. The map could have been half of it's current size and still had the same content and no loss would have been felt.
When they implemented the item system in this game they thought about quantity over quality. If you find 2-3 good legendary weapons all game that you will enjoy using for their stats and special effects you are lucky. At least they did a transmog system so you can change the appearance of weapons and armor.
I didn't like the naval combat. I feel like almost every game after Black Flag (not going to mention the garbage game that AC 3 was) needs to have naval combat. The combat in this game most of the time was infuriating. It annoyed me so much that i went and unlocked all of the map without doing any quests just to get the fast travel points so i don't need to touch the ship if it's not required.
The Lost Tales of Greece
This was a disappointment except 1-2 missions. They feel like an after thought with how they are implemented and i just rushed through the missions to be done with them faster.
Legacy of the First Blade
I like how they tied Origins with Odyssey with this dlc, but i hate how they wrote the characters and it was too cliche for my liking.
Hated the ending of the dlc. I knew it got some heat from fans on the internet, but was not expecting it to be this garbage.
The Fate of Atlantis
Somehow they managed to make an even worse dlc than Legacy of the First Blade, for that i applaud them. All 3 episodes of this dlc feel like naruto filler when the tv show got ahead of the manga (been there and watched it go down live). I have no idea how they managed to make quests with zero meaning, but appear to have meaning and they push you towards your goal.
If it wasn't for the fact that I made a huge investment of time in the game and i wanted to finish everything i would have quit this garbage dlc 30 minutes into it.
Conclusion
Even tho i had more bad things to say about the game i would still recommend this game if it's on a sale. Just be on the lookout for the sales since this goes for around 80% off.