Just had a thought about the 2nd Duke3d episode, when I watched the level names of the old beta con file.
It said the ep. started with 3 moonbase levels, then 2 space stations then a power station. I assume the power station is either Lunar Reactor or Warp Factor. This order doesn't make sense at first, but at second it can be close to some reality.
IMO Spaceport fits well as the 1st level of the episode. Then after reaching the transport, we travel to the Tiberius Station moonbase level. Then we got into Lunar Reactor and Dark Side. From Dark Side we teleport into an alien site, then into Occuppied Territory. After the Battlelord ending, we fall into the Overlord level. Fusion Station fits as a secret level, has no keycards etc., and can be reached from the well known area of Dark Side. Both level finish similarly, just that Dark Side is filled up with water.
It would make sense for several reasons:
1. The 7 AHB levels look very coherent, while the Levelord levels has an entire different atmosphere. The AHB levels consistently use the same door sounds, the same textures, while Incubator and Warp Factor are very different (actually these levels are coherent with each other too...)
2. I always thought the episode slowed down and got easier when I reached Tiberius Station. Fusion Station and esp. Occ. Territory were difficult levels and had pre-boss feeling. I felt that I started a new episode with Tib. Station.
3. There are no link between Warp Factor and Fusion Station. How did I get from that power bunker to a large alienated area?
My fictional order of E2 would be:
L1: Spaceport
L2: Tiberius Station
L3: Lunar Reactor
L4: Dark Side
Secret Level: Fusion Station
L5: Occuppied Territory
L6: Overlord
Just my 2 cents.