Briton Ian Poulter, American Bubba Watson and Australian Adam Scott were among those to raise concerns.
"It is far from unplayable, but we do hear player comment and we're not so insular as to ignore it," R&A chief executive Peter Dawson said.
Poulter was unhappy after his round of 72, saying it was disappointing when good shots were not being rewarded properly.
"Unfortunately the guys this afternoon will struggle with a few pin positions," Poulter tweeted. "8th hole is a joke, 18th needs a windmill & clown face."
Watson, who shot a one-under-par 70, said it was the most difficult start to a British Open he could remember.
"This is the toughest I've ever seen on the first day," the American told reporters. "The pin locations, the burned out greens, the firmness of the greens and the firmness of the fairways."
Dawson said the extremely hot weather had made the course more difficult but he was happy with the set-up.
"We've got the conditions here that we really like to have - hard, fast and running," he said. "We set up the course to test the players' course management strategy.
"We're obviously very conscious of player comment and we'll take that into account tonight."
U.S. Masters champion Scott, who shot 71, was another player to voice concerns.
"Some of the pin spots are really borderline," the Australian said. "It's so dry and it's pretty spooky out there."
Dawson said the R&A was very happy with the scoring in the first round.
"It's about what we would expect, 5-under par is about where we'd expect it to be," said Dawson, referring to the round of 66 posted by leader Zach Johnson.
"I think it is giving us the right results, very testing and tough but I guess it is the Open Championship."
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