At the murder scene, Marty curls his left thumb and forefinger into a tight circle and looks through it to see the dog's collar. That is not a silly affectation. It works like reducing the aperture on a camera to sharpen the focus of your eyesight.
Marty Eels has a seriously overpacked wallet. George Costanza from Seinfeld (1989) also has a stuffed wallet. Both are played by Jason Alexander.
When Marty Eels begs Captain Stottlemeyer "Put me in, Coach" - this is from the John Fogerty song "Center Field".
The Pontiac Firebird Marty Eels drives is the same one Peter La Fleur (played by Vince Vaughn drives in the movie Dodgeball.