The Arrival

First off, big fan of the X-Files, so that definitely got my attention when I read the description. As for the piece itself, I think the composition is pretty good. The mountains drawing the eye back down to that person on the ground are definitely a nice touch.

I think those clouds in front of the vessel could be removed. It looks a bit odd and doesn't actually make the ship look bigger in my eyes. Instead, I would probably make the gradient from light to dark a bit more extreme so that by the time you see the top there is only a dark outline on the ship. You might even consider darkening the sky to really keep our eyes focused on that beam!

I would also increase the intensity of the light on the ground which spirals out from the beam. That thing looks bright, and hot, so the surrounding area should better reflect it. Maybe have the light create a spiderweb up the sides of those rocks?

That's all I've got off hand. It seems like the piece isn't completely polished yet so I didn't pick at it too harshly.