Amulet Titan relies on Amulet of Vigor to untap its bounce lands and Urza's Saga to power out Primeval Titan and Cultivator Colossus, so Meltdown is a real answer. With X=1 it destroys Amulet of Vigor (mana value 1), and with X=0 it destroys the Construct tokens that Urza's Saga makes (mana value 0). Keep in mind that Meltdown also hits our own Mishra's Bauble, and that Urza's Saga itself is an enchantment land, so Meltdown cannot touch it. Spell Snare is narrower, since it only counters a spell with mana value 2. Its realistic targets are Malevolent Rumble, Aftermath Analyst, and Green Sun's Zenith for X=1. It cannot hit Arboreal Grazer (mana value 1) or Summoner's Pact (mana value 0). We trim Violent Urge and one Mishra's Bauble since this matchup is a race against their ramp rather than a combat-trick fight, and we need our limited disruption slots to matter. Keep the aggressive core intact since beating Amulet Titan is primarily about applying pressure before they assemble Scapeshift or a big Primeval Titan turn.