See "Handguns of the World" by Ezell. Page 672.
The similarity between the Walther 1944 (I mistakenly said 1945 before) experimental pistol was the fact that the breech block and locking block were separate components that were pinned into place.
This is not to be confused with their 1944 vintage Walther Volkspistole which was made of sheet metal and used a Browning-style lockup.
In the current Mauser M2, the slide rails are in two sets - a forward set milled or cast into the top of the same block that cams the bolt on the barrel (and the same unit that holds the trigger), and a rear set in another block in the rear which holds the ejector and other mechanical parts.
It looks like they made the pistol with as few machined parts as possible, and only using steel where absolutely necessary. On the other hand, we never have to worry about aluminum to steel contact on this pistol - the slide rails are steel and the slide is steel. There is little or no direct contact with the frame (which is aluminum). You can see a lot of daylight through the side of the M2 between the slide and frame.
I can write more about the M2 (in fact, I have an easier reassembly trick for those who have complained on this board about how hard it supposedly is to reassemble) in my next posting. For a pistol that costs between 400 and 500 dollars, it seems remarkably robust (despite the designed-in engineering shortcuts).
The similarity I mentioned earlier about the early Mauser Nickl pistol and this current model is the exact same position (9 and 12 o'clock) bolt lug positions, the same 6 o'clock bolt cam stud position, and the same clockwise rotation to approximately 1 o'clock to unlock the bolt after about 8mm of rearward travel.
The Steyr Hahn, the recently defunct Colt rotating bolt model, and a few others are not very similar - not as obviously close to the Nickl and Walther models.