Parallels between Leone and Tarantino.
My theory: Landa set the whole thing up, practically from the start. He sees where the war is going and designs his escape, right from the jump. The improvisations he requires are just the path that happens, it could have been another way. But he exploits and manipulates all the characters all the way to the last second when he gets his highly Inglorious surprise.
(1) Patisserie: Hellstrom --> Shosanna --> Venue Change --> Landa (he toys with Shosanna (ordering milk, remembering the milk discussion at the farmhouse) to tell us he knows who she is. He knows about the venue change. He has all the elements. Does he already know about the Basterds? While we don't know yet, it doesn't really matter, he is looking ahead to Shosanna's plot; the means don't matter. We will find out later that in fact he
does.)
(2A) Bar: Hellstrom again --> Basterds --> Hammersmark, then later
(2B) Theater: Hammersmark --> Landa "If the shoe fits" (we are left with a question: why does Landa seem to go nuts and kill Hammersmark? It makes no sense and does not follow from anything we know about him. Yet.)
(3) Restaurant: Aldo --> Landa "Shoe's on the other foot" because Tarantino can't help himself tying a second pair of scenes together plus you know foot fetish (Oh,
now we find out Landa knew about the Basterds from the interrogations of their "Swastika-marked survivors." From the shoe, he strongly suspects Hammersmark had tried to set up the Basterds at the bar (sorry, Hellstrom). Therefore, we now understand he killed Hammersmark to tie up that loose end to allow the plot, his bargaining chip, to survive.)
These three scenes alone are great, but the combination tells me Landa planned everything nearly from the start.
He just miscalculated. He did not apply his level of brutality to Aldo, so he loses because he can't conceive that Aldo and Landa -- names that are practically mirrors -- are the same except for uniform. Ironically, we knew this from Aldo's first speech. We are the detective who is finally a step ahead of The Detective. And scene.