This card's been nagging at the back of my brain for a while, dunno what took me so long to bring this stuff up:
The board's "columns" are loosely defined, a column could be interpreted a number of ways. How many columns are there, and what cards do they include? When you answer this, it should also be in the description. Or maybe try to get Zanz to make the rows line up, heh!
Even as simple damage, this card has an advantage over Firestorm - it can hit immaterial creatures, like Flooding can. As instant-kill, it will wipe the entire enemy field clean eventually, assuming your opponent has no Boneyard.
Combine this with PA and a form of stalling - Sundials, Phase Shields, Diamond Shield, even most forms of healing - and it will be absolutely brutal against any creature-based deck - every basic rush, every standard entropy or time rainbow, every fractal deck... Bone Wall would be a nice choice in combination with this too.
I rarely say this, and I never say it lightly - this card seems OP. It breaks too many deck concepts, even with its slow-acting-ness. Changing it to damage would balance it a bit better, can't go over 3 though, since it ignores quint.