Unfortunately, they are next to useless. This wouldn't normally be a problem except that they restart from where they left off, so if you are watching from this point you are reading subtitles from action that took place over 2 minutes previously. This continues right through to the end of the movie and into the final credits. Anyone with hearing impairment who may want to watch this movie be warned - the first half will be all you can completely enjoy. It is the best placed layer change I have seen.
Dialogue is a mixed bag.
Much of the scintillating script is delivered at breakneck speed in the noisy chaos of the boiler room and can therefore become muddled or misunderstood. I was actually discovering what was being said for the first time. Nicky Katt 's character Greg is the biggest offender for the mumbles. None of this is a problem with the actual audio soundtrack, more of a feature of the movie. There is an abundant overuse of the F word though, so be warned if sensitive ears are listening.