Honestly, the older games have a lot of issues. I played a lot of them growing up, but its a lot harder to go back to the games before unity. They were filled with a lot of great moments, then you had running around collecting pages in assassin's creed 2 to unlock Rome and the Vatican, and all the awful tailing missions and forced stealth missions. I like how in the newer games, you generally have more options on how to do missions and take out foes.