W00t, thanks for the critique
First and foremost, like I said the layout hasn't been completed yet and I didn't expect you to really get anywhere (quickly, or at all!) without noclip. Also there were 'HOM' effects as some areas were still cordoned off.
As far as I'm aware, doorways are as wide as Valve's, but I'll stick in some more clip brushes to help you get around. And I'll go about sorting out some of those ugly lights and corridors post haste.
The force field which you said you couldn't work out uses that 'gizmo' to power it, as seen in the latter parts of the single player game. I'm sure once someone fries you with one of the energy balls or you get stuck on the RPG ledge you'll figure it out 
Those damn plants growing on the ground, I can't get rid of them as they automatically appear with that ground texture! I'll do something with the water though, someone else said they couldn't really see it.
Did you see the dropship landing at all?
And Cassius, where in particular did you think the rocks looked a bit jagged, around the water or just everywhere?
Anyway, thanks a lot for the critique, lots of good feedback to work on
I guess the texture limit will bother some people, but hey, I've used more than Valve did in most of their later single player levels and am personally happy with it!