A couple more for ya:
In SECBASE, I was able to jump-crouch up the front of the troop transport outside, and from there get onto the second floor of the base. I could then take the elevator down, without getting the keycard or having any enemies spawned inside.
In TALAY, at the very beginning when you turn around to shoot the stormtrooper, there are two rebel posters on the left-hand wall. There is a clipping problem here, just walk forward hugging the wall and you will get stuck.
While I'm on the clipping issue, I'll mention that there are a few control console models in the rebel base that you can walk through.
And this is more of a gameplay issue: throughout the levels (especially TALAY) there are many small ledges and pillars that stick out from the walls. I found this to be slightly frustrating getting caught up all the time, as I hug the walls a lot when I play. I'm going to suggest that if there are narrow tunnels or elevators (SEWERS) that have detail sticking out, that these in-between areas get a clip brush.
Well, that's all for now. I'm off to play the demo for the 50th time:D...