The game takes place between episodes 3 and 4. The specific block of time the game actually covers is longer than a typical movie - the game takes place over several years, and includes several distinct passages of time. Yoda appears in one part, as well as a few other familiar characters throughout the course of the adventure.
The main character in the game was inspired by Lucas himself - it is the story of a Force-user that escaped Order 66, and survived The Clone Wars. They kept mentioning how the character is very much Samuri-inspired.
The panel mentioned they did focus testing recently, which they are taking valuable feedback from. They declined to talk about length of game, but emphasized the high replayability of the title due to various game physics engines that make the game different every time. They said the game can be played through arcade style, or can be savored a bit more if desired.
The story is epic, but also manages to include some humor. Lucas specifically mentioned it was crucial to Star Wars, and the make sure it was included. As dark as it is, there's some funny parts, according to the designers. The director confirmed there will be a multiplayer component, but no announcements right now.