Kotaku describes SUPERHOT (all caps) as being "like Braid with guns" , which is definitely an apt description. Basically, it's a first person shooter in which strategy plays an even bigger part than just mindlessly running and gunning. Because time marches forward only when you do.
The trailer doesn't do much in telling the whole story; SUPERHOT is one of those things that needs to be played to be understood. But at the very least, the trailer is still cool to look at: