CURATOR COMMENT
Please put a space on either side of the pipe divider in the title (Graviton Barrier | Graviton Bulwark).
Pretty art. It seems balanced enough, but what's the thematic reasoning behind letting delayed or frozen creatures attack? It doesn't seem to make much sense to me.
The original concept was based off the Holtzman shield in dune which blocks fast moving objects but lets through slow moving ones (aka stops a bullet but lets through a knife). the thematic is not as clear because the name obviously cannot be holtzman shield due to copyright reasons.
Fixed.
Also yeah darkrobe's idea had the original thematic. I'm trying to think of how to explain it, it makes sense in my head but the way this works (slightly different than holtzman's shield) is that it is some sort of magical shield placed on the Elementals arm that generates the field shone in the art. This field makes it so the harder a creature trys to approach the elemental, the stronger the field pushes the creature away. Only creatures that are perfectly still (frozen, delayed, or "stopped" or "patient") wil pass through it as the shield will actually ( this is where it fails a bit) pull the creature in, causing it to collide with the Elemental as though attacking. Because a turn in elements is appx. six seconds (based on how fast rush decks work) creatures lack the time to just stop moving. If you want to say turns last longer than they actually do in the game, I think one could safely say that the monsters aren't intelligent enough to figure out how this shield works.
Hopefully this makes sense, and it could use a little more work, but there are other cards with just as many thematic problems already in the game (how does a voodoo doll become enraged and attack? etc.) I'll try to refine the thematic and clean it up as I go.
TL;DR: Magical gravity forces.