That means, for example, if you have a Lord of Accursed on the battlefield ("Other Zombies you control get +1/+1"), all your attacking and blocking graveyard creatures (which Over My Dead Bodies makes into Zombies) would get +1/+1 while in combat
Furthermore, this design has a nod in its name toward the "Final Fantasy VIII" boss monstrosity's hallmark attack, the 10,000 Needles, which directly kills enemies in the computer game
If you gain some life, you get energy, and you can use that energy to pay into the X part f the cost instead of mana
So by relying on your lands only to cast your commander (the strategy on which most decks are based) you will find that every other card type becomes much more impactful
Let me know your thoughts and experiences in the comments below, or chat about it over in the official Draftsim Discord