Wow, that deck is nasty.
Wouldn't wanna play a Red or Black deck against that.
But before you have a lock on, you're pretty vulnerable.
Have you considered more defensive parts?
Propaganda 
?
Pendrell Mists 
?
Or card draw in
Rhystic Study 
or
Phyrexian Arena 
?
All of these options require mana to stop them, maybe you could also pop in
Ankh of mishra 
?
It would work well with Bloodchief Ascension, getting it active quite quickly.
Other effects like
Static Orb 
or
Winter Orb 
would make these effects a soft lock for a few turns, and force your opponents to play lands if they wanted to actually play anything.
A lot of your cards really nerf creature cards, putting them into the graveyard from the top of the deck , or at upkeep next turn.
Vengeful Pharaoh 
?
It seems like a better choice than No Mercy, as it's a lot less vulnerable than No mercy to a sweeper. (back to nature, cough cough)
Plus, if your life is getting low, you could actually play it on the field.
If you have some extra draw on the field, this sucker's downside (no draw) wouldn't be so bad.
