Zombicide is a wildly popular co-op boardgame, where the players are survivors amidst a post-apocalyptic world overrun by zombies. Read all about it on Zombicide.com.
This kickstarter adds a new chapter in the form of a stand-alone game "Prison Outbreak", and also an addon set "Toxic City Mall", plus a load of kickstarter exclusive survivors and other goodies.
The more people join in on this kickstarter, the more goodies people will get. So if you like the game, and I sure do, head to the page and choose a pledge level. If you want to add optional addons, just add the total amount to your pledge amount total without changing your pledge level. A survey will be sent out after the KS ends, and you will be able to fill in what you chose as extras above your pledge level.