The video features graphics and sound lifted from Half-Life 2 and a setting that strongly echoes Valve's bleak Combine-infested world. There's also the fact that the title of the video, What's in the Box?, is a strong allusion to Valve's last Half-Life-based release, the Orange Box.
The site linked in the video, whatsinthebox.nl, leads to a single Flash-based page with movie-style credits, a pulsating box and the header, "Soon the world will find out."
Find out what? Portal 2 is coming? Half-Life 3? Or is this just a commercial for a really durable line of coveralls? Watch here and commence speculation!