1 Jul 2012
If you cast a card “without paying its mana cost,” you can’t pay any alternative costs. You can pay additional costs such as kicker costs. If the card has mandatory additional costs, you must pay those.
1 Jul 2012
The copy you cast first will already be on the stack when you cast the other copy. If that spell targets a spell, you may choose the first copy as a legal target.
1 Jul 2012
If one of Spelltwine’s targets is illegal when Spelltwine tries to resolve, you’ll still exile and copy the remaining legal target.
1 Jul 2012
Spelltwine has two targets: the instant or sorcery card in your graveyard and the one in an opponent’s graveyard. You can’t cast Spelltwine unless you can choose both legal targets.
1 Jul 2012
You can cast the copies in either order.
1 Jul 2012
If the card has X in its mana cost, you must choose 0 as its value.
1 Jul 2012
The copies are created in exile and cast from exile. The cards remain exiled.