Amulet Titan relies on a fragile, nonbasic-heavy manabase full of bounce lands and Urza's Saga to enable Amulet of Vigor and Primeval Titan chains, so Fulminator Mage is a huge tempo blow that can single-handedly wreck their setup. Force of Vigor destroys Amulet of Vigor or a completed Urza's Saga before it assembles a Construct army, and can be cast for free when we need to act on their turn. Grist, the Hunger Tide adds pressure and removal for Primeval Titan or Cultivator Colossus once they land. We trim smaller value creatures for more proactive disruption since punishing their manabase is the core game plan.