Anthony Edwards and William H. Macy both appeared together in ER (1994) later in 1994. Susan Sarandon would also later make a guest appearance. That series would also prove to be the breakout role for George Clooney, who would work with director Joel Schumacher in Batman & Robin (1997).
Polly Holliday appears in archival footage as Mark watches TV in a hospital waiting area. Holliday later played "Momma Love" in the TV series adapted from "The Client."
At the time of the film, the only prior acting experience Brad Renfro had was a school production about D.A.R.E (Drug and Alcohol Resistance Education). Renfro was arrested and convicted several times for drugs possession prior to his death in 2008.
When Romey re-inserts the hose and handkerchief into the tailpipe (after Mark removed it) his fingers and hand touches the tailpipe a number of times. This is impossible without burning the fingers. Also, the handkerchief after coming out of the tailpipe is as clean as when it went in.
The Falcon 900 aircraft they depart in has its nose gear scissors disconnected as it taxis away, other shots it's connected. (Probably being towed away)