In fact for shits 'n' giggles try running a Mac executable on a Windows machine or vice versa. In fact Linux is one of the only systems that can really do that consistently, I've got a few programs on my netbook that I basically forget are running through an environment.
Uhhhh... what? I'm not aware of that ever happening as you seem to envision it.
Mac applications, while technically UNIX-based, are VERY different from Linux applications and I have yet to see one run on a Linux machine in any way, using any software bar virtualization software that all three OSes can use. It's also worth noting that Mac applications
Windows applications can run using WINE or CrossOver, but though that's fairly decent, it's not the holy grail and doesn't do everything right - and it's certainly a far cry from being in any way native in terms of support.
Obviously, Linux apps don't run on either system unless they're ported or virutalized.
Please tell me what you use to run Windows and Mac applications with that degree of seamlessness (unless by an "environment" you mean Virtualbox or some other virtual machine, which is in fact cross-platform).
On topic, though, the video was very cute and well-done, though I did see the sync a bit off. I honestly kinda preferred the original one on deadtrolls.com though.