This is an interesting plot, done only a few times, in which we follow the Axis invaders behind Allied lines ("The 49th Parallel", "Das Boot" are probably the two definitive classics of this sort).
5 German commandos go on a far fetched plot to assassinate the Allied supreme leaders. To its credit, the officer in charge admits it is half cocked, and only agrees to allow the 5 to go because it doesn't interfere with any other plans. Realistic? Probably not, but probably more realistic than people today realize.
Ken Clark, who is famous for the super cheese scene of being the blonde muscle man embracing the scantily clad blonde in one hand and packing a pistol in the other in "Attack of the Giant Leeches", goes to portraying a very believable bad guy. This was very typical of the evil Nazi. His cruelty and savagery come across in a convincing way in mixing with a civilized world. Very similar to the evil leader in "The 49th Parallel" in being a three dimensional and credible bad guy.
The second in command is also believable, and quite credible for the time, as a German officer who is not a Nazi. The film serves much as a vehicle for this character to develop. In fact, even the other 3 Germans develop some character in their limited lines. While serving as an action desert film, it also gives some good characters. We probably would've liked to see more of them.
And just about everything that happens, plot twists and characters who die, go totally against the grain for the late 1960s and early 1970s. We know, of course, the mission will fail, but we are surprised to see how some of this comes about.
This may classify as just short of a hidden gem.
