Also the title is also known as Academy Apocalypse.
Wikipedia - High School of the Dead
Official Website - 学園黙示録
Horriblesubs' sub is just a copy of the streamed broadcast. Commie's actually fansubbing the series. Also, this anime just got licensed so sites like ANN are streaming it so I'm not sure if Commie has to stop subbing or not.
Anyway, I watched today and it resembles the manga pretty good. The art style is pretty close. This is gonna be pretty awesome anime.
Apparently, the manga gets another volume this month along with the anime so pretty good stuff eh?