Looks good, the only thing missing is a more coherent narrative. Right now it reads as if both sides are attackers, with a fairly symmetrical battleground. Maybe the portal side is the attackers; and they get a different bonus for controlling the various objectives (e.g. controlling the portal gives the attackers some minor reinforcements each turn, controlling the fortress gives the defenders a big gun, that sorta thing.) Also, are there 2 bridges, or more than 2? And minor sidenote; be carefull with how many flyers you allow. I can imagine that certain army lists will just ruin the entire thing by simply ignoring the river