Fortress Tactics offense

Offense is relatively simple. The two players who will usually rush the opposing fortress are the point and the person to the right of point. The person to the left of point can rush, but usually doesn't get to do so right away. So the two rushers need to account for at least one opponent between them, two is preferred, on their way to the zone. If they don't even get one, they need to double back and go pick one off. The reason is simple, there's probably one goalie at the zone, and if they don't kill anyone on their way, they leave their defense outnumbered.

The left of point is usually an offensive position as well, but his is a little unique from the rest. He has to take out one opponent before he can rush the zone, and it's this fact that usually causes him to show up after the other two. It's not a big deal because three players at the enemy's fortress wind up killing each other in their rush for the zone. So left of point is usually better off playing a forward defensive position until it's time to go to the zone. When he goes to the zone, his best bet is usually to prevent opponents from returning to protect the zone and buying time for the two rushers (who should already be there) to take the zone. In either capacity, he's playing a defensive role, but he's playing it in offensive positions.

All other players are defensive players until the opposing team has been reduced to a point where it's safe to leave the goalie by himself.

Offensive Roles

On a 7 person team, you will have 3 offensive players. The number of offensive players generally starts at 2 because 2 are required to take the opponent's fortress. The role of the offense is pretty simple. Rush the opposing team's fortress, and on the way take out 1-2 of the opposing team members. Depending on how the line separates, each player will have a slightly different role.

Center

The center has all the responsibility, so choose your center wisely. He has to come up with a way for the line to split without killing everybody, usually by making a call of some sort. After the line splits, he will be the fastest player on his team, typically, and you'll want him to take advantage of the speed to get as close to the opposing fortress as possible.

Which direction he turns is going to depend on a number of things. If the line splits early, he can turn left. If the line splits late, he must turn right, because there's an opposing wall on his left.

The Responsibility of the Center

This is a very important role in the offense. The center really needs to be in tactical command of the team, so if your center isn't in tactical command, you need to get rid of him. Since the server chooses who goes in what positions, you might need to take drastic measures to get rid of the guy. Since he's an offensive player, he needs to be making calls to tell the offense when to attack, when to pull back, and so forth. He's also the player who will get killed in the first 5 seconds of play if he doesn't do something to split up the line, so he has the most to lose by not taking his role seriously.

On your team, it may not make sense to actually give tactical command to the center. In that case, if your team captain isn't close enough to the center to split the line properly, the center will still need to make the appropriate call to split the line. So he doesn't have to be in tactical command of the team to split the line, but in that case he needs to respect the team captain's wishes about splitting the line.

Offensive Guards

I call the other two offensive players "guards" for lack of a better word, and the term is borrowed from basketball. These are the players immediately to the left and right of the center. Their individual roles will vary depending on how the line breaks. If the line breaks early, then they each need to account for one opponent before rushing the zone. If the line breaks late, then the guard on the right and the center together need to account for one opponent before rushing the zone and the guard on the left must account for one opponent before rushing the zone.

If the offense doesn't account for any opponents, then their defense is likely to be overwhelmed. In that case, and regardless of that fact, they need to take the opposing team's fortress as quickly as possible. It goes without saying that they need to take the opposing team's fortress before their own defense falls.

Rushing the Fortress

Rushing the fortress only takes one offensive player, but the player that gets there first needs to decide quickly if he can take it by himself. If not, then he needs to wait for assistance before proceeding. There are plenty of tactics that work when taking a fortress, but not all of them work against the same people. The only rule that seems to hold true is that two attackers can take a fortress, but three can't. So when the third attacker arrives, he needs to hold back and be prepared to lend assistance while playing a rear guard position in case the opponent's team arrives to help defend.