They are standard H.264 (a variant of MPEG4) files. If you have an H.264 codec and a player that understands Quicktime headers, they should play fine on any machine. Well, one with enough power anyhow. My Powerbook 1.25 struggles to maintain a perfect playback rate on the 720p ones. The 1080p ones choke it badly.

Although I have to admit, I can't quickly find a H.264 codec for Windows. I'm sure one exists, just can't find one that works to play these files in Media Player Classic.