I didn't think that a rock giant would be an interesting villain for the Thundercats to face, but this episode was suspenseful from start to finish. I think what made the villain so scary was the fact that he was emotionless and expressionless. He marches straight toward Cat's Lair creating great seismic disturbances. He roars and breathes fire. I thought it was great that when the Thundercats finally see him, they don't say anything; they simply jump in the Thundertank and run.
The entire episode took place during a rainstorm, so it was really dark. The Thunderkittens briefly run into Jackalman and give him a run for his money. The Thundertank has a wild scene chomping through a mountain.
Lion-O's final battle with the rock giant is awesome. He uses the Sword of Omens to split a boulder thrown at him in half.