I work as a professional game designer, so I know good game design when I see it.
This game was so well designed, and it shows.
One of my favorite board games ever, and I own tons of them.
This game is also VERY hard! That is part of what makes it so great: you are always struggling to survive every turn.
The COOP element just makes it a blast. Never tried the competitive component, although the game is already too hard to get any worse.
Even if you like competition, the COOP element will still satisfy. Each player has a secret object they have to selfishly accomplish while simultaneously helping the team to win. Even losers can be winners by sacrificing their win for the team.
A huge hit with everyone I've ever played it with.