Agt played the opening right, but there's not much you can do against this strategy and this map. I won the opening battle of the scis and explored both planets the next turn. He killed my single attack and col coming up the next turn, but that really didn't matter much. The next turn I brought in another attack and col, plus the sci that had explored west. He only had 2 ships, so didn't attack.
The next turn he focused on colonizing his planets, so left me alone to colonize Trash Heap. I hadn't built anything else so that I would hit BR-2 the next turn. I overbuilt 7 BR-2 ships, giving me those plus the 2 BR-1 ships left to attack his Home World. Given that short of notice he never had a chance.