I like where this is going

Very dark atmosphere at the start. I'm liking the use of bass in ambient, as it's mostly tricky to keep it "chill" enough with a lot of bass, I suppose.

I think the attack on that first pad could be a bit long, so it's more like zwwwhoooaa then bwoaa, if you know what I mean.

I would have kept the drums on a slightly lower volume. Maybe try varying them a little more, simply making your pattern longer will give you some room to play, and you can still keep it to one pattern then. Also, I find that bathing those drums in some reverb can give a wonderful touch to them in the genre. Just make sure to set the low cut high enough or it'll sound messy.

The thin arpeggio is a nice touch. Something to try for the full version is straying from the simple up-down pattern and switching some notes around, it might get you interesting results.

I can definitely hear this is still going somewhere.. bigger, which is part of its progressive nature. I'm curious to see where you'll be going with this. So far I definitely like it.

Keep it up sir!