Hi there, first thing I would suggest is adding more removal. As far as I can see your only removal spell is
Zombie Apocalypse 
, and that is situational at best. You need to add in some spot removal like
Tragic Slip 
,
Victim of Night 
possibly,
Dead Weight 
and if you can get your hands on any
Sever the Bloodline 
s. Also i'd say
Moan of the Unhallowed 
is better than
Reap the Seagraf 
so I'd switch the numbers of them around. I'm also not a fan of
Cellar Door 
or
Rooftop Storm 
, they are a bit slow IMO.
Highborn Ghoul 
is better than
Walking Corpse 
aswell, so if you could add/swap more of them it would help. 1 card I don't think pulls its weight is
Sightless Ghoul 
, I just hate this card, and if you can try and replace it with something else it would be beneficial, maybe replace them with more
Abattoir Ghoul 
s if you want to keep something elase at the 4-drop slot.
The main problem with
Zombies in Block as opposed to mono
is the mana base. In standard you have access to 8 copies of dual lands but in Block we're not so lucky, thats why people mainly play mono
Zombies in Block. But if you want to stick with
, thats fine, but i'd put in a few
Evolving Wilds 
to help out the mana base. I've just realised that you are also only running 17 lands. That isn't nearly enough. I'd recommend running 23 minimum as you have a couple of high mana cost cards, if you cut those you could go to 22 lands i suppose, as your overall curve isn't that high.
The best card Zombies have in their arsenal i'd say is
Geralf's Messenger 
, however he is rather expensive and hard to acquire. Same goes for
Gravecrawler 
, I see you have 1 copy which is good but if possible I'd increase the number, but I understand if you can't because these 2 cards are tough to get your hands on. 1 rare that should't be too tough to get hold of is
Skirsdag High Priest 
he's not a Zombie but he's an excellent 2-drop that alot of Zombie decks have had alot of success with.
I'm sure there's alot more other people could help you with, but I hope this helps.
P.S Good luck in your upcoming tourneys.
