We start by clearing out the first big area with crates and stormtroopers. Then we jump on this here lamp post, or the big-ass piping further in the background, to get on the slope above.
Then we jump up this ledge by the big conveyor belt/bridge that used to be patrolled by rocket troopers.
From there, we take a jump around the corner to land on this slope.
After which we jog around a bit.
Until we find a wall that we jump over. NSFDrumpf.
Then it's as simple as jumping on this little slope.
And finally climbing this platform.
And bang, we're at the entrance to the Doomgiver.
r00fles!