Islands of Death - need help with scenario

[moonmagi]

Hey all, first post here. Wanted to ask for some help on a scenario i've been working on. The map and rules are in the pdf below. I'm new at making these, so I figure the rules aren't explained very well. Just ask if you have any questions and i'll try to explain it better.

My friend and I played this with the rules set the way they are now, and we found the defender to have a big advantage over the attacker. So we've been trying to think of various ways to make it more balanced. Any suggestions you guys have are welcome.

Oh, the maps are in order from left to right starting with the one in the upper right hand corner.