I can't see anything particularly wrong with your play. You probably should have opened Bridge/Silver instead of Silver/Silver as you were buying one later anyways, but that's going to have a pretty marginal effect on the game. Your opponent was lucky to pick up a Governor and Alchemist on turns 3/4 and then to draw them together on turn 6 and trash an Estate into a Potion thus ensuring he'll hit his Potions for Alchemists more often. I don't love his strategy, but tactically he plays the game very well. This might be a question for the simulators or wiser players than myself, but personally I'd say he played a marginal strategy and had nice shuffle luck.