I'm a little late to the game, but here are all of the new releases I saw in 2015, ranked.

Mistress America, dir. Noah Baumbach
Nasty Baby, dir. Sebastián Silva
The Wolfpack, dir. Crystal Moselle
Tangerine, dir. Sean S. Baker
Spotlight, dir. Tom McCarthy
Amy, dir. Asif Kapadia
Best of Enemies, dir. Morgan Neville & Robert Gordon
7 Chinese Brothers, dir. Bob Byington
Kurt Cobain: Montage of Heck, dir. Brett Morgen
Straight Outta Compton, dir. F. Gary Gray
Going Clear: Scientology and the Prison of Belief, dir. Alex Gibney
Me and Earl and the Dying Girl, dir. Alfonso Gomez-Rejon
Mad Max: Fury Road, dir. George Miller
Dope, dir. Rick Famuyiwa
Results, dir. Andrew Bujalski
Digging for Fire, dir. Joe Swanberg
The Big Short, dir. Adam McKay
Star Wars: The Force Awakens, dir. J.J. Abrams
Bridge of Spies, dir. Steven Spielberg
The End of the Tour, dir. James Ponsoldt
Entourage, dir. Doug Ellin
What Happened, Miss Simone?, dir. Liz Garbus
Get Hard, dir. Etan Cohen
The Stanford Prison Experiment, dir. Kyle Patrick Alvarez
Trainwreck, dir. Judd Apatow
Steve Jobs, dir. Danny Boyle
Hot Girls Wanted, dir. Ronna Gradus & Jill Bauer
Queen of Earth, dir. Alex Ross Perry
Sisters, dir. Jason Moore
Fifty Shades of Gray, dir. Sam Taylor-Johnson
Entertainment, dir. Rick Alverson

I still have yet to see a number of films that would likely have a place near the top of this list (Chi-Raq, The Hateful Eight, Phoenix, The Lobster, Anomalisa, In Jackson Heights, Carol, etc.), but I'll get around to those soon enough.