Pandemic is a cooperative game (similar to Shadows Over Camelot and Battlestar Galactica)in which the different players take on different roles to fight several new diseases that are striking the world to prevent them from becoming major outbreaks that overrun the world.
There are several positives about Pandemic. First of all, the mechanics of the game work very well and are very balanced. None of the roles are overpowered compared to the others (though the Medic might be close). Next, the difficulty level is adjustable through the number of "Epidemic" cards that are included. The more Epidemics that you include, the harder the game becomes. Thirdly, the game is easy to learn, and yet challenging enough that you can play it often without feeling like you will always win, and so it is ideal for bringing in new players (read, "the ladies" - this is one that my wife enjoys playing with me).
The final thing to note about Pandemic will be a positive to some people and a negative to others. Pandemic is strictly cooperative. Shadows Over Camelot can have a traitor (which is optional) and in Battlestar Galactica it is just a matter of time until someone betrays you, Pandemic will never have a traitor, unless you just have a person you're playing with who refuses to work with the rest of you (and then it's not the game's fault).
Overall, I would give Pandemic a 9.0/10. It is one of the best cooperative games I have ever played, and I would highly recommend it to anyone that enjoys that style of game.
Now, with that said, it's time to get to On the Brink. The first thing that I noticed when opening this expansion is that there isn't really that much in the box. At the $30 MSRP, you don't really get that many pieces - there are about 20 new cards, a notepad of paper, one new disease, new wooden pawns to represent new roles, and some petri-dishes that you can use to hold the disease cubes.
Once I got past the limited number of pieces, On the Brink is pretty good. The first thing that it does is expand the standard game - there are new Role options, it adds the option of playing with a 5th player, and it adds an extra "Epidemic" card so that you can make the game ridiculously hard.
The next thing that On the Brink gives you are new ways of playing the game. There are three new game modes, some of which can be played together. In the first game mode (the one that we played), you replace the Epidemic cards with special new Epidemic cards, and you identify one of the diseases as the "Virulent Strain". This was very enjoyable, and still stayed with the theme of Pandemic, which to me is a positive. The next mode allows for a "Mutating Strand", which, again would add difficulty and complexity but would still stay with the normal Pandemic theme.
In the final mode, one of the players takes on the role of the "Bio-Terrorist". This mode would be for the players that didn't like the fact that Pandemic was cooperative in the first place, and all of the players that are not the Bio-Terrorist are trying to locate him so that they can stop him.
Overall, my biggest complaint with this game is what I stated previously - there's not that much to it for the $30 sticker price. However, with that said, I liked Pandemic, and this allowed me to get more playability out of a game that I already enjoyed, so it winds up coming in at an 8.0/10.
Like cooperative games? You might also be interested in reading about Lord of the Rings, Legend of Drizzt, or Yggdrasil. Or, for a longer review, you might check out the Board Game Family's Pandemic Review.