If you're looking for a scare this Halloween weekend, look no further than Jake Gyllenhaal's new thriller, "Nightcrawler."

Written and directed by Dan Gilroy, and not based on the X-Man of the same name, "Nightcrawler" sees Gyllenhaal playing a TV cameraman who works in the world of violent and tragic news. The result: Gyllenhaal turning in a transformative and harrowing performance that many critics are describing as his best work yet.

Here's what you need to know about "Nightcrawler" as it hits theaters this weekend:

The Graphic News

"The theme of 'Nightcrawler,' written and directed by Dan Gilroy, is the excesses of the 'if it bleeds, it leads' culture of local television news, a world where the words 'what you are about to see is graphic' are both a warning and a come-on. But the main attraction of this film is not what goes on behind the scenes at Los Angeles' fictional KWLA, Channel 6, but rather an examination of the character and career trajectory of one Lou Bloom, the young man in a hurry that Gyllenhaal brings to life with extraordinary conviction." — Kenneth Turan, The Los Angeles Times

The Dirty News

"'Nightcrawler,' the aptly titled directing debut of veteran Hollywood screenwriter Dan Gilroy, may be a little too sleazy and knowing for its own good. After watching Jake Gyllenhaal’s intense and unsettling performance as a sociopathic TV news cameraman chasing the most gruesome late-night stories across Los Angeles, you may need a shower, a Valium and a triple shot of whiskey, without feeling entirely sure you want to wake up the next day." — Andrew O'Hehir, Salon.com

The Dirty Newsman

"As Lou Bloom, a freelance TV news cameraman with a nose for graphic tragedy, Jake Gyllenhaal creeped me out big-time. I mean that as high praise. Gyllenhaal, in a poisonously potent performance, twitches with morbid excitement. Bloom will crawl into any L.A. rat hole or car wreck to produce video or dig out a photo he can sell to a TV news director (Rene Russo, tart-tongued and terrific), just to momentarily sate the public's appetite for gory digital sensation." — Peter Travers, Rolling Stone

The Man Behind the Dirty Newsman

"Thirty pounds lighter, all cheekbones and bulging eyes, Gyllenhaal plays one of the year's most memorable characters in this dark, provocative drama. … Gyllenhaal — whose recent roles in 'End of Watch,' 'Prisoners' and 'Enemy' have been terrific — continues his impressive streak. This may well be his best-ever performance, in a compelling film that works equally well as a dynamic thriller, a psychological study, a grim satire and a searing indictment of contemporary journalism." — Claudia Puig, USA Today

The Final Word

"Deeply philosophical while remaining both captivating and entertaining, Nightcrawler is that rare breed of worm, one with an Art Film heart and a Hollywood shine. It may be too dark and challenging for some, too dry and calculating for others. For me, however, this is the kind of thing I adore, something both caustic and cerebral, a wonderfully subtle film with moments of kinetic brashness. Brilliant performances, impeccable execution and a laudable directorial debut, Nightcrawler is easily one of this year's best films." — Jason Gorber, Twitch

"Nightcrawler" is in theaters now.