Get your Gris on
Simply get an opponent down to 10 life, and then cast this spell at instant speed and that's a win
And this card is incredibly powerful for Commander, as well as other kitchen table brews
The included eldrazi titans (Ulamog, the Ceaseless Hunger, Ulamog, the Infinite Gyre, and Kozilek, Butcher of Truth) are the coolest and most powerful, but dont discount others like Void Winnower or even Meteor Golem
The Commander all-star Sol Ring represents the serialized nineteen rings given to the men, elves, and dwarves of the world with a new mythic rare, The One Ring, getting a mechanically unique card all its own
In cEDH, Gifts Ungiven will also often just straight up tutor for a package of cards where there is no wrong choice