can falling star target separate units with damage

Yes, Falling Star can target separate units.

The card text specifically states: "Deal 3 to a unit. Deal 3 to a unit. (You can choose different units.)"

According to the official FAQ and game rules:

• Simultaneous Declaration: You must declare both targets at the same time when you play the card and put it on the chain.
• Targeting the Same Unit: You are also allowed to target the same unit with both instances of 3 damage (for a total of 6) to ensure it is killed.
• Deflect: If you target a unit with Deflect, you must pay the Deflect cost for each instance of damage targeting it. If you target the same unit twice, you pay the Deflect cost twice.
• Bonus Damage: If you have an effect that grants Bonus Damage (like Annie, Fiery), the bonus applies to each instance of damage individually. For example, with +1 Bonus Damage, Falling Star would deal 4 damage to the first target and 4 damage to the second target.