What's the word on the sequel?

So What's the word on the sequel? Nothing shows up on the director's IMDB page, or elsewhere. I'm ready for the next installment!

What other movies focus on the horrors of tight spaces and claustrophobia? Even if they aren't "Horror" movies. I am fascinated with segments that showcase claustrophobia, especially in a sense where I can imagine how terrifying and awful the situation would be. Don't ask me why I get sick pleasure from doing that myself... I truly hate tight, enclosed spaces. I'm looking for more movies that focus on this sort of thing. The deeper, the darker, the tighter and the more agonizing; the better!

Here's some off the top of my head that I've already seen:
The Descent
Crawl or Die (my current winner)
Cube
I watched "As Above, So Below" - but I was high or something and I don't remember any of it, so I can't remember if there was any good stuff there.
I've got "Submerged" - I just haven't watched it yet.