Well i can't really comment on the other levels like yourself, given i haven't played them as i have Aztec. Though i'd say it's easier than a number of levels. I break the level down into sections and try and improve each part.
Room 1: Start to door opening level with gun
Room 2: Door to door opening level with gun obviously
Black Room: Door to crossing over the mainframe
Glass: Mainframe to pausing at the glass
Corridor: Coming out of pause at glass to pause at vent shootout.
Room of Death: Coming out of pause at vent to text showing up after insertion.
I did some rough comparison times for each section awhile back with a few players, prob still have the times somewhere. Mostly for SA/00. It was good as a rough guide to see where i was sloppy and losing time. I was quite good on my 00 starts, which i had more practice at given i was in that first room more than the other rooms

. Its fairly simple really, only so many guards in each room and there shouldn't be any suprises, so no real need to move at the end on SA/00. Caverns and Control have so many more skill factors. Aztec is more like surface or something, just need to be accurate and fast with your shooting, and carry the speed throughout. Yeah glass fags are annoying, prob in the top 5 for guard gayness in GE.