First off 2x Heavy Storm?? You can only have 1 in your deck!
Drop:
2x Chaos Sorceror
2x Offerings to The Doomed
2x Mask Of Darkness

Add:
2 Elemental Burst
1 Mystical SPace Typhoon
1x Element Dragon
1x Element Saurus
1x Element Valkyrie
1x Element Doom

SORRY FOR THE DOUBLE POST! MY INTERNET IS MESSED UP X__X;

This deck can't use Elemental Burst. Can't add that.

But as for fixes:

-1 Heavy Storm
+1 Call of the Haunted
+1 Graceful Charity
-1 Chaos Sorcerer
+1 Sinister Serpent (never know when you'll need that)
+1 Mystical Space Typhoon
-1 Last Will
-1 Offerings to the Doomed

If anything, you can compare your deck to my deck.

9/10

y not instead of on ritual weapon u use a heart of clear water. ref my zombie deck in sig please. thank u.