Dead Block is currently available for download on Xbox Live Arcade.
240 MS Points ($3) will grant players access to the More Dead to Block map pack, which includes a Turkish Bath, a Slaughter House, a Motel and an Office Building level. Each map is playable both in single-player and via three-player online co-op. We'd suggest the latter -- facing the undead alone is kind of like covering all of your clothes in A-1 and taking a weekend getaway to Cannibal Town.
Admittedly, Cannibal Town does have a sweet rollercoaster.