by phillier937
As a co-op this is a good choice for a family game. I don't think you'll be disappointed.I love the game and can not even imagine playing it without on the brink - I have plenty of games where I keep the add on separated in it's own box or bags - not this one. The only technical change is are the added roles, added special cards and some card clarifications/corrections as well as adding a 5th player. With a smaller group you suggested the 5th player may not be important and I know someone who only plays it solo.
The other less important things are smaller pawns - the old ones are HUGE and take up so much board space and then there are the awesomely cool petrie dishes (ameritrasher in me coming out). The alternative game play options also add in more play-ability / variety.
Patrick