Sometimes HDR is minimal..though I found it hard to really see any differences between #1 & #2.
Did you do a screenshot of #1 and #2? they have the side letterbox that looks like a screen shot or something.
As for #3 the image itself is closer, as stated above, because of the lens size/length. I remember when my wife and I took the "same shot" her with a 3GS and me with the 4, they showed different parts because of the lens length.
The first two are screen shots because I have geographical tagging on and did not think it would effect anything if it was a screenshot