There are actually 2 soundtracks:
VTCL-60246 | Koreha Zombie Desuka? Meccha Sounyuuka & Meccha Soundtrack... - VGMdb (
http://vgmdb.net/album/24298)
VTCL-60243 | Koreha Zombie Desuka? Meccha Soundtrack - VGMdb (
http://vgmdb.net/album/22780)
I'm pretty sure you can find them in the anime music section of the forum.