Laura Gretsky, a former KGB field agent, stabs Castillo from behind using a five-inch blade with her right hand. It should have been a fatal wound to the heart. Later we see that Castillo has a minor wound through the meat of his left side. that is painful but definitely not fatal.
Around 27:40, when Castillo talks to Martie, boy's head position is inconsistent between shots.
The license plate on the front of Tubbs' car reads "Cowboy Cadillac." This would seem to be very uninformed. The term cowboy Cadillac refers to a hybrid sedan / pickup such as the Cheverolet El Camino and the Ford Ranchero. It is actually a bit of an insult, as this is not a pickup truck for a working cowboy but for someone who pretends to be a cowboy.
Getting shot at point blank range with a 44 magnum would cause a huge amount of tissue damage. There is very little blood on his shirt, nor is he even holding that shoulder as if it had taken a round.