Here is a photo of the floor. I spoke with Danny from the painting crew about it, since they are the ones sealing the floors. He said that they would be filling in those cracks with some sort of epoxy -- it doesn't hide the cracks, but it does prevent further cracking. He also said that doing a hand applied stain would make it look better. I thought we had ruled that out at one point because of cost, but he said it was only $1.20 sq. ft. for staining. We'd love to make it a warmer, richer reddish/brownish/orangish color if it really is going to be that affordable.
A couple of people have mentioned now that this wasn't from the sandblasting; that just revealed cracks that were already there from the foundation settling.