Yes, your opponent made mistakes. It was an enterprising idea, but not really sound.
What he said. If it would have worked against a player of x rating is irrelevant. You should play the moves you think are best no matter what your opponent's rating.
http://www.chess.com/livechess/game.html?id=46161456 so I took a huge risk sacrificing a bishop in order to poke a hole in the kings defences. I may have won but was it a good strategy, or did my opponent just make mistakes? In a game against a 1700 rated player, would this strategy work? In a game against another 1300 player, would this strategy still work?