I’m still enjoying playing this game, after a few sequences in you receive weapon upgrades from your old friend Leonardo & he asks you to take down some weapons he has created for the Borga. I have taken down the machine gun which was fairly easy apart from you had to stay undetected & the naval ship. This was an enjoyable quest and had you using the invention to destroy the Borga ships.
On my first visit to the Coliseum I also unlocked the Romulus Lairs quests which generally have you jumping around underground lairs & chasing after an individual to kill. These are similar to the tombs in Assassins Creed 2, they are difficult & challenging. There are six in Brotherhood to unlock & once you have completed them all you get access to some rare armour & weapons, so worth doing.
There is so much to do in this game from missions, shop quests, contracts, treasure maps & lairs. I think I will be playing this game yet for a while.