Is there a way to open a .unity3d file in the editor?

I accidentally deleted by assets essential for my game, and they are nowhere to be found. Luckily, at the end of each day, I made a version of my project and saved it as a web player application (version_7.unity3d). Now I would like to extract the deleted assets from my last saved version. Is this possible?

No, you can’t open a .unity3d webplayer build in the editor (why did you have the conscience to create a daily backup of your build but not a backup of your source files?!).

It is possible to extract assets from a .unity3d file, just as it’s possible to rip the assets from any game, but you’ll have to use external tools to do so and you’re unlikely to find a detailed explanation of how to do that here since it could be used for nefarious purposes…