If Falling Comet is played in a showdown and deals damage higher than the opposing unit's might, does it kill the unit before the damage phase of the showdown?

Ruling: Yes, if Falling Comet deals damage equal to or greater than the unit's might, it kills the unit before combat damage is dealt.

Sequence:

• Actions can be played when entering a showdown, starting a chain
• Players can play reactions to that action
• The chain resolves (spells take effect)
• After the chain resolves, players can start a new chain
• If no new chain is started, combat damage is dealt
• Units killed by spells before combat damage do not deal their combat damage

Nuances:

• If a spell deals damage less than a unit's might, the unit is damaged but survives and will still deal its full might as combat damage (though it needs less additional damage to be destroyed)