Well I'm on Series one, and even managing to beat the computer on normal for the first time, there's still some stuff that just seems random! How exactly do the attacks work? I can't fathom the icons. Some cards have multi direction attacks but only attack one way. Some seem to attack differently between summoned and activated attacks. Some seem to target allies whereas others don't. Some don't attack when summoned, only in defence. It's way confusing!
As examples, the Se Hollyn Fortress has a red arrow to a yellow explosion in front, like most cards, but it won't attack when summoned. Biolith Bomber has attack in four directions with pink arrows, and red arrow forwards. When summoned I have a choice who to attack in its line of sight, but I've also had it attack multiple targets. I don't know what criteria is needed for the multiple attack. If I place a Biolith Battle Chariot that has one of mine and an enemy card it its arc of fire, will it attack both? What about if I activate it? And Hellfire Spitter has pink arrows in three direction onto blank spaces, and a red arrow into a yellow explosion. I guess the pink arrows show options for attacks, but what's with the explosion icon?
Ok Shifty I'm going to help you out here some.
For the Se Hollyn Fortress for instance, it has the 'fortress' qualifier in italics in the card text; this means that it can't be used to attack offensively, and only counterattacks. That's why it doesn't attack when you summon it though, and why you can't attack with it when it's already in play.
The different attack modes....
Well, when you see a card that has multiple directions of attack, the solid red arrows represent the number. So like the bomber for instance is omni-directional in its attack paths, but only one of the red arrows is a deep solid red; that means when it attacks, you choose one specific square along any of its possible vectors. Same with the hellfire spiiters - but the bomber icon shows that it has a range of two squares in any direction, where the hellfire spitters card shows a range of only one.
Now with the battle chariot, both arrows are solid, which means that when you attack (or counterattack) any card/creature in either of those fields (whether friend or foe) will be subject to the attack. The attack itself only triggers though when there's an opponents card at play; so if you summoned it to finish the game instead of attack an enemy, and allied creatures occupied both target fields, it wouldn't attack. But if it was in play, an allied creature was occupying a target field, and the enemy summoned a creature to attack the chariot, the allied creature would get caught up in the chariots counter-attack.
Aspects like these are some of what give the game its greatest depth; it's awesome to try and see where you can use non-obvious means of attack on your opponent, and sometimes that includes baiting a stronger foe in order to wrap up your true target in the scuffle.
As for the cards that hit both targets in front of them, that's indicated by a solid long arrow going through both squares. Where the bomber and such indicate their method by several segmented arrows, a card like the harpoonsman has the arrow run through. Similar to the battle chariot example above, any creatures in those two squares - whether friend or foe - will get caught up in the attack should the harpoonsman engage.
Anyway hope this helps some!