Fin,
What makes it fun is you actually make decisions, so while its a dice rolling game, it's not JUST the roll of the dice; you make decisions that determine your success or failure, and you can play conservatively or take more risk.
Set up: The players are all Zombies trying to eat Braaaainssss... the first to get to 13 Braaaains wins. The dice represent human victims. The dice have 3 symbols: Braaaaaaiinnnnns, Shotgun blasts, and feets.
Gameplay: shake the cup and draw out three dice without looking. Roll them. If you get Braaaainnnns, you keep them (yummy). If you get shot gun blasts you keep those: accumulate three or roll three at once and your turn is over (I'll return to feets in a second). You can score your Braaaaains and end your turn if you're not blasted to pieces (that is, have three shotgun blasts) or push your luck and press on.
To press on, you keep any dice with feets on them, and draw from the cup 1-3 more dice without looking at them, to make a hand of three dice (You always roll three dice). Once you draw from the cup, you MUST roll the dice.
If you get three blasts your turn ends, but otherwise you can stop or continue after each roll and rack up your brrraaaaaaiinnnnsssss. Once one player gets to 13 braaaaaaaaains, everyone else gets last licks.
So that's the rules, but besides the braaaainnnns thing, the game play is fun. It just is fun. Even my wife who was like, "what the hell is wrong with you?" enjoyed playing it. The probability and the gambling-like rolling of dice... well, I don't have to explain why that's fun to you.
Something that adds depth is the color of the dice. Green ones are easy targets (3 braaaaains, 2 feets, 1 shotgun). Yellow are average folk (2 each of blasts, feets, braaaains), and red dice are bad ass (3 blasts, 2 feets, 1 braaaain). So you can guess your odds as you play and make informed decisions about your odds. That said, it's wonderful to watch someone else get three shotgun blasts with three green dice. HA!
At $13.13 with a very sturdy cup (that also fits 1 set of Chuthulu dice) and 13 custom made dice (yes 13 is a running joke/design element as well as the braaaainnnns thing) I think it's a good value. It's re-playable and just plain fun.
So just buy it already.
If you're going to Gencon there will probably be a sale too.
If you haven't already, check out the link in the OP to see another review and example of play.