So I was controlling the troops but /vst/ was giving me strategic orders. I don't think amphibious landings were seriously considered because we (purple) were being pressed so hard. We started out by cutting off and encircling the big enemy push in the south. Once that pocket was reduced we pushed forward on the southern coastal road until stopped.
Then there was a debate on what to do (attack in the north, do a paratrooper landing behind enemy lines, try to cut off the enemy in the southern swamp). We ended up encircling the enemy in the southern swamp but it was difficult and took time to reduce the pocket because of the terrain.
After that, the enemy had taken such major losses that we were able to fairly easily break through their southern and northern ends of the line and move up the coastal roads, fending off counterattacks. By that point our steamroller had all the momentum and we surged forward, crushing everything.