Can you react between the two damage instances of Falling Star?

Ruling: No, you cannot react between the two damage instances of Falling Star. The spell resolves as a single item on the chain, executing all its instructions from top to bottom without pausing for reactions between damage instances.

Sequence:

• You play Falling Star and declare all targets for both damage instances
• Players have the opportunity to play reactions to the spell itself before it resolves
• Once all players pass, the spell resolves completely: it deals the first 3 damage, then immediately deals the second 3 damage
• No player can add new items to the chain between the two damage events during resolution

Nuances:

• While you cannot react between the damage instances, you can play reactions (like Counter Strike) before the spell resolves to create delayed replacement effects
• If you play multiple replacement effects before resolution, they will all be active when Falling Star resolves, allowing you to prevent multiple instances of damage as they occur