Actually, they spread out the features. So disc 2 (R3) has some of the features (including Mr. Concepcion's video). It's also have the game demo yata but I haven't popped it into my PC so not sure. The 2-discs' features mirror's R1's two-pack* with the exception of Secrets of the Furious Five short film which is one of those watch-once and forget video, it's more suited for kids, nice artwork though.
R1's Kung Fu Panda is three disc actually, with the third disc being the Activision game (Don't know if it's a demo) but look like a full game disc to me with 'Games For Windows' label.
R3 has the Sam Concepcion video and an extra Po around the World feature which is basically the last fight scene between Po and Tai Lung set to different languages, basically useless.
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*Secrets of the Furious Five disc (R1) includes some features and they are all ported over to the R3 disc 2 (with the exception of the short film itself).