Hub based levels are tricky for a level designer, they are simple to make and plan but to keep them interesting without the player having to backtrack is what the designer has to overcome.
The whole point of a Hub is to have the player go through a central point in the map multiple times to proceed. The danger of this is that the player will get bored returning to the same place over and over. Games like Batman Arkham Asylum use the idea of a Hub extremely well, it does this by restricting the player from reaching certain areas too soon and by providing multiple routes to reach an area.
From analysing levels from Batman I found that many of the corridors were shaped to make a “U” shape which loops back on itself to minimise backtracking for the player. There is no point in making the player go back along the same corridor they have already conquered. Therefore, I tried to implement this into the Doom level I designed.
I wanted all the branches to have some kind of loop feature where the player returns to the hub without having to go back the way they came too much.
With regard to the branching pathways there also needed to be variety, therefore one path with an acid lake that has very irregular edges and one with lava with a more standard shape helped to differentiate stages of the level.
For most paths I implemented the “U” shape seen in Batman which John Romero refers to as the “Classic Doom U shape” in which you enter from one side of the sector and you can see the other side from the entrance, but it takes a roundabout path to reach the other side.
When it came to encounters what encapsulates a lot of the Doom experience is the ambushes, therefore including them is almost compulsory. I tried to place these encounters at interesting points in the level, particularly when you reach the blue and red keys.
Lastly is the boss battle, I didn’t want a standard boss battle. So instead of having the player fight one big scary Cyberdemon I set up a bunch of triggers in a room which opened doors on the walls which unleash waves of enemies, so the more the player moves around the more enemies they release. I found this to be an interesting final battle however it presents problems with pacing and sometimes enemies get stuck in the doorways they are meant to burst out of.
If I were to improve the level further I would be sure to set dress the place better as well as lay out the textures to make everything a bit more visually interesting.