It hasn’t been an easy journey for The Flash. The movie has been hampered by a floundering, then rebooted DC expanded cinematic universe that lags far behind Marvel’s, a heavy schedule of reshoots and a lead actor in and out of legal trouble.

But at CinemaCon film festival this week, that all faded into the background as audiences got their first preview six weeks ahead of the rest of the public. The reactions were, for the most part, glowing: some called it superb, one of DC’s best and funniest, and also one of the great all-time super hero movies.

While that’s a triumph for director Andy Muschietti, there’s another talent behind the screen — even if few are aware.

“My job is very detail oriented,” Paul Austerberry explained to CBC News. “Half the things we do, some people will see, some people won’t.”