Revenge of the Sith marks the "dark hour" of the Star Wars saga - the rise of the Empire. There are lightsaber duels all over the place, the Jedi are confused, and war is at its bloody peak. Many of the older characters seen or referred to in the original trilogy are, by this point, introduced and their relationships established with the destruction of the Jedi order.
Trips are fast, geography is hazy, and it's not entirely clear what's going on in neutral systems. Clonetroopers are highly competent, droids are comically incapable, and Jedi not as prescient as they'd like. This movie explores cyborgs to a degree.
Although the film was a special effects bonanza with well-choreographed action, this conclusion left a number of details unclear.