You have some great imagery going (which make for some vivid scenes)...but there's nothing really tying it all together.
Even if the overarching storyline is going to remain in the realm of the relatively familiar nightmare sequence (completely okay) this needs to go in one direction or the other - as in, you need to add some meat to the imagery by tying in a more distinct reason for it (plot), or you need to go all the way in the other direction and make this a more "indulgent" exploration of this particular man's sort of nightmare.
You might be able to combine those two goals if you really work at it (especially since you don't have to worry as much about a page length requirement, if you don't plan to shoot for the fest). Personally, I would at least try to do this with a follow-up draft, because in the best case scenario it will work wonderfully, and in the worst you'll have a better idea of which way to go with it (more story or more loosely-tied-together but nonetheless compelling psychologically grounded images).
If it helps...an idea...
He's sitting at his desk at the end of the day. Probably there's a phone on the desk. Maybe (everything else remaining the same in terms of setting and scene) we meet him a half a minute earlier...when he's getting off the phone with his wife...with their conversation providing a clue into perhaps one of the potential underlying psychological causes of the nightmare? The only danger there, I guess, would be the possibility of making that goal too obvious.
Doesn't have to be something exactly ike that, but again, there's some solid vivid imagery popping off the page...it just needs to be married to some sort of a glimpse into this character. The imagery will hit harder (and resonate) once we can associate with him in some way. Succeeding at this may mean sacrificing or altering some of your nightmare sequences...but hey...that's why drafting sucks, right?
