Near the end of the movie Wahlberg has a noticeable 20 pound weight lose and hair is longer, but the next scene he is back to the previous build.
At approximately 30 minutes, Gil's glasses switch back and forth between on and off.
A cougar chasing Sonny Fisher growls like a jaguar and, to a lesser extent, a tiger (both are roaring cats (genus Panthera)). Cougars are more related to smaller cats (subfamily Felinae).