After Mike introduces Frank and Dito, the trio leaves Franks apartment. The cross the street and start to discuss wages, Job - from the bible, and Frank tells Mike he gets a raise. "well you just got a raise then, for the band". As soon as he finishes "for the band" there is a pay phone emerging from the left side of the screen. Verizon. The year is 1986 in the movie, however Verizon Wireless began operations on April 4, 2000. WSII.
When Antonio attacks Reaper in the convenience store, it is night time. Immediately after this happens, Dito and Mike go to Frank's apartment. The lighting and view outside the windows make it obvious that it is daytime when they are at Frank's, but as soon as they leave, it is nighttime again.
For the first scene in the 1980s, Dito walks home with Antonio and Nerf. When they go into Dito's house - and their clothing implies it's continuous - Giuseppe has suddenly joined them and Nerf is nowhere to be seen.
The song "New York Groove" is incorrectly credited to KISS. While he was a member of KISS at the time, and while KISS performed this song during their tours in the late 70's and early 80's, the song is actually from Ace Frehley's 1978 self titled solo album.
The goof item below may give away important plot points.
When Antonio goes in to kill Reaper, he, Nerf, and Dito are standing up, then duck when Reaper's friends leave. The shops next to the bodega have windows open. A couple of seconds later, Antonio gets up with the baseball bat and the windows are shut with a security backing behind them.