I have played this 3 times and enjoyed it every time. Plenty of replayability .
We have only played turn by turn which is fun and can imagine the intensity of playing real time. I enjoyed it playing 2 , 4 and 6 player and am yet to play 8. If you play 2 player you take on the other 3 roles as well as your own so a bit more to manage. It's not hard to understand but you do need to know each roles' role. Good quality game, worth buying.
This is like battle ship but you play as a team on a submarine. It takes a little bit of time to understand the roles of each player, but once you get going, a very fun and entertaining game!