Can you react before the second time Falling Star deals damage, or does the whole card resolve without being able to react to it?

Ruling: You can react at multiple points when Falling Star is played. Falling Star uses reflexive triggers that create two separate "deal 3 damage" abilities on the chain, allowing reactions between them.

Sequence:

• When Falling Star is played, you can react before it resolves
• After Falling Star resolves, two damage triggers go onto the chain with targets chosen - you can react before any damage happens
• After the first damage resolves, you can react before the second damage trigger resolves
• After the second damage resolves, the chain is usually empty (no further reaction opportunity unless other triggers/reactions occurred)

Nuances:

• You can only respond with reactions, not regular spells
• You can Wind Wall the main spell itself, but cannot Wind Wall the triggers once the main spell has resolved
• Priority passes after each thing resolves on the chain, as long as something else remains on the chain