[quote]I like the idea that higher-tier Rapid-Fire attacks allow multiple attacks per card… I think that the attacks from any single card should only be able to be used on a single opponent, but that chained Rapid-Fire cards could potentially target different opponents with each card.[/quote]
So a single card targets a single opponent; if the card has multiple attacks, each targets the same opponent. Multiple targets require multiple rapid-fire cards, unless some effect specifically breaks this rule? I can see the utility of tracking attacks this way in general, although if we go this way, we should have some card effect that breaks it, allowing the card to target an additional opponent (or all opponents if high-tier effect or socket kicker?). Each opponent resolves the attack individually". Essentially, the effect would mirror the card, its full effect brought to bear against another opponent. Because this requires two cards (the attack and the modifier to increase target opponents), this effect should effectively increase the total potential damage done, instead of splitting the attack among multiple targets.
Since upgraded Strikes deal increasing amounts of damage to a single target, and rapid-fire attacks deal the same damage with increasing numbers of attacks, what if Return attacks
For example, if a card counts as 2 attacks for 1 each, both attacks must be defended against by a single opponent. If the attacker (or another opponent) also drops a mirror effect card on the attack, the card is now 4 attacks for 1 damage, 2 pairs of attacks targeting 2 opponents. The mirror effect should be able to mirror the attack against a single opponent as well (all 4 attacks against the same player) to keep it useful during 1-on-1 games, or else have some other 2-player utility. Maybe the simplest way of communicating this mechanic is to have the modifier card clone the targeted attack; since it would be considered another card, it can target the same or another...