It's a little bit hard to get the exact gamestate until the log is on CR, but some points:
1) I think passing on Salvager when going for Spice Merchant is almost always a mistake. When you clean your Coppers, you also want to get rid of these Estates. I would even say that going for SM when there is no other trasher for the Estates is very often a mistake. At least you need a good reason for it. Trashing Coppers and leaving the Estates in the deck gives you a very bad money distribution, especially in the early game, and you need to get Silvers to compensate. But you don't really want Silvers, you want Mining Village, Rabble, Goons, Nobles. I think SM is certainly right here, you want a dense deck to play many Goons, but you also need money in the beginning, where a sole Spice Merchant has problems, because the Estates stay in deck. Salvager will help here.
2) I think you got too many Goons to early. The first Goons is certainly more valuable than everything else, especially because the attack prevents you opponent from getting them themselves. But in the end, you want to build an engine, you eventually want many Goons, so you need a way to draw and play them all. Goons does not help you with that. You bought Goons in 8,10,13,16, and Nobles in 14. You had 3 MV in turn 13, so at this point, you can play 4 terminal actions at most per turn, but already had 3 Goons. And you need some of them to draw your deck. So after the first or second Goons, you need to get your engine rolling before you target more Goons. If you can't draw and play them, they don't help. And the points are not so important this early, and ignoring the points, the second and later Goons are only Woodcutters. Whose buys probably don't need yet.
3) In turn 17, you buys Gold, Copper, Copper, in turn 18 a Province. Maybe the game state was that you really needed these points for your opponent not to finish the game next turn, but I don't think that is the case, as the game lastet much longer. And with this buys, you basically destroyed your chance to get a big Goons turns later. If you already have 4 Goons, and started buying an engine, you want to continue this way. So the Gold could definitely have been something else (not sure whats left), and you can really pass on the 4 points from Copper if that prevents you from playing your 4 Goons later in one turn. You can also pass on the 6 points from the Province. You must pass on these. If your opponent has a Goons engine running, or almost running, that can play say 3 Goons each turn, you can't win against this by trying to empty the Provinces and scoring say 9 VPs per turn. Your only chance is to get a better engine running before the game ends to catch up.
That's what I see. Finally, of course these Goons vs. Goons games are always very non-linear. Just because you lost 200:20, this does not have to mean you played much worse. The one engine kicks in a little earlier as the other, maybe because of luck, maybe because it was played a little better, and soon you keep playing 3-card hands every turn, while your opponents engine keeps delivering him 3 or more parts of even this engine per turn along with dozens of VPs, trashing more trash and even has some 5-card hands to start with, because you missed your Goons.
