Assassin's Creed 4: Black Flag's present day sequences are almost entirely optional, Ubisoft has confirmed, with players only needing to spend a maximum of 20-25 minutes in the modern day if they so wish.

"In total, if you were to do everything in the present day - find everything, hack every computer, access every room - it's a solid three to five hours," game director Ashraf Ismail told the Ubi Blog.

"For the main path - the stuff you're required to do - it's somewhere between 20 and 25 minutes. You leave the Animus five times during the game's main path and each time you're there for about three to four minutes."

He added: "We pretty much tried to boil it down to its most core essence because we know there are people out there who really don't like the present day, and that's okay. You don't have to like it, but it's part of the brand. For the people who like the present day and are big fans, we put in a lot of fan service and a lot of fun optional content. You get to choose if you want it or not."

The modern day sequences will help tell the game's "meta story" and be used "as an opportunity to say goodbye to Desmond" - the hero of the previous Assassin's Creed games.

"You have to hack computers and figure out how to access certain rooms and get through security," continued Ismail. "There is gameplay in just being able to access that stuff. When you access it, the content you find is a reward for us. Through this content you see what happens to Desmond after Assassin's Creed III. We used it as an opportunity to say goodbye to Desmond. There's actually a lot of stuff linked to him that you find."

Desmond won't be the only character making a re-appearance in Assassin's Creed 4 either, with Ismail promising "awesome cameos" from familiar characters.

Could Ezio, Connor or Altair be making a comeback in this year's game?

Assassin's Creed 4: Black Flag launches on Xbox 360 and PlayStation 3 on November 1, with Xbox One, PlayStation 4, PC and Wii U versions following on November 22.