The above video shows Hex in action; the game is currently in closed beta testing so things could currently be different. Gameplay wise the game looks like your typical Magic clone, which to be fair almost every single collectible card game is. However where I thing Wizards of the Coats are really aiming their lawsuit is that graphically Hex bares more than a passing resemblance to Magic Duels of the Planeswalkers.
The important term here is ‘Trade Dress’ which, according to Wikipedia “refers to characteristics of the visual appearance of a product or its packaging”. No look at two screenshots of the game side by side and there is more than a passing resemblance between the two.
It’s going to be interesting to see how his pans out because if elements of Hex’s gameplay come into question then nearly every single collectible card game and derivative is going to be under scrutiny.