Revealing mistake: As Hogan goes through the hole to the ladder, the "rock" he brushes against flexes for a second. Likewise, when Kinch climbs through, the "rock" under his hand flexes and mashes down as his weight is on it.
Revealing mistake: When Schultz checks the barbed wire to see if it is fixed now, he noticeably wiggles the vertical wire, but only barely touches the horizontal one - because it is rigged to come apart, and will again if he handles it too roughly.
Revealing mistake: When the boys are working on the fence, when the camera is on Hogan, you can see a modern metal building in the distance.
Hogan and the Lady Doctor - S2-E20
Revealing mistake: As the truck pulls into the laboratory yard, the buildings of the city surrounding the studio backlot are seen.
Revealing mistake: As Burkhalter's car comes into the camp, it's easy to see that it's a re-use of stock footage.
Heil Klink - S2-E22
Revealing mistake: After Browner gets out of the staff car and is going inside, as the camera pans to the left following him, you see the Desilu Studios water tower.
Funny Thing Happened on the Way to London - S3-E5
Revealing mistake: When the staff car enters the camp, you see a set of tire tracks leading up to, and stopping at, Klink's position. When the car comes in, it precisely follows the tracks, suggesting previous takes.
Revealing mistake: After the cell door blows, you can see the fuse of the stick of "dynamite" Newkirk placed still burning on the ground. Since the dynamite would blow when the fuse is burnt up, that literally can't happen. (00:22:40)
An Evening of Generals - S3-E13
Revealing mistake: The silver rack with bowls starts moving a second before the rocking explosion.
Everybody Loves a Snowman - S3-E14
Revealing mistake: As the sink with the fake tunnel is prepared, just before Newkirk goes over to set things up, you can see movement through a crack in the door. It's Schultz, Hochstetter, and Klink, waiting their cue to enter.
Everybody Loves a Snowman - S3-E14
Revealing mistake: When Hochstetter goes to open the snowman, you can see the plug is a poorly disguised piece of wood, as well as the piece of metal around the opening in the snowman.
Is There a Doctor in the House? - S3-E18
Revealing mistake: As Carter blows into the bottom of the oven, the suds that hit Newkirk in the face come out in a thin stream on top, not out of the whole stovepipe.
Sticky Wicket Newkirk - S3-E20
Revealing mistake: When Hochstetter goes to open the window in Klink's office after the explosion rocks the camp, look at the background. You can see the studio lighting shining on the matte painting of the camp yard.
Clearance Sale at the Black Market - S4-E1
Revealing mistake: After Kiegel shoots out the bulb the light takes a couple of extra seconds to fade out.
Clearance Sale at the Black Market - S4-E1
Revealing mistake: The Major goes to shoot out the light that the boys have turned on so Kinch can get the pictures. The first shot is angled too low to hit the bulb, but there is no impact on the front of the door's crosspiece; the smoke and dust comes from behind it. The second shot gets the bulb, but there is no muzzle flash, just sound. Also, there is no impact mark on the brick wall behind the bulb.
Man's Best Friend Is Not His Dog - S4-E6
Revealing mistake: As Schultz holds Newkirk's hat during the search, you can see "Dawson" written on the inside band. This was to insure that Richard Dawson (Newkirk) always had the right wardrobe pieces.
Color the Luftwaffe Red - S4-E8
Revealing mistake: When the truck with Hogan and company pulls up to the Luftwaffe HQ, the camera pans to the right to look at Klink getting out of the side car. When the camera cuts back to Hogan and company, they shake as if the truck just stopped, but it can be seen that the truck was stationary.
Will the Blue Baron Strike Again? - S4-E12
Revealing mistake: When Hogan, Newkirk, and Carter are at the Blue Baron's secret airfield, Hogan opens the barrel and stuffs in a rag and lights it so it will be a flare for the Allied bombers. The flight line and the planes on it are an obvious cutout. The fire couldn't have spread to the surrounding ground like it was shown. Also, when the bombs were going off on the airfield, you can see that the explosions are very small charges behind the cut outs.
Revealing mistake: While talking about Von Baler's daughter, Hogan is facing the building talking with Carter and Newkirk. Behind him is an open area of the camp. If you look, you can see that there is no guard in The Tower, no shadow of The Tower of the guard hut (the sun is behind them and Hogan), and the snow is piled up about three feet behind Hogan, suggesting that the background is a wall mural in the studio.
Revealing mistake: When Schultz is on the way out after giving the guys the news about the inspections and roll calls, you can plainly see that the background behind him is a matte painting. This is easy to spot because the building in the distance is lighter in color, and there are ripples in the fabric used.
Answer: Nimrod's actual identity was never revealed in the series. It was only known that he was a British intelligence agent. Nimrod was not Colonel Klink. Hogan had only implied it was him as a ruse to get Klink returned as camp commandant, not wanting him replaced by someone more competent who would impede the Heroes war activities. The term "nimrod" is also slang for a nerdy, doofus type of person, though it's unclear why that was his code name.
raywest ★
"Nimrod" is originally a king and hero mentioned in the Tanach and taken into the Bible and the Koran. His name is often used in the sense of "stalker," "hunter," and sometimes figuratively as "womanizer" as in "hunter of women." I've never seen it used to denote a nerdy person, and although I cannot disprove that connotation, I think given his role, the traditional meaning is more likely the intended one.
Doc ★
It's widespread enough that Wikipedia has an entire section on it: https://en.wikipedia.org/wiki/Nimrod#In_popular_culture