Engine: Unreal
I created this level primarily in order to practice and refine my level design skills as well as getting more familiar with tools in the Unreal Engine.
I chose to frame the game as being created for a Fantasy Action Game in the style of popular games like Dark Souls due to my familiarity and interest in those types of games.
Level Walkthrough
The level takes place on the edges of a city near a giant mausoleum. Enemies from the graves below have caused a collapse and have sunk a number of nearby buildings and continues to pull them down. 
The player begins the level near the intact part of the city and beholds the mausoleum and the collapse in front of them as they enter. They are provided a place of safety through a checkpoint from which they respawn upon their death.
There are doors to the left and right of the player. To the player's right as they enter is the path forward. The doorway to the player's left cannot be opened from the side they start on.
The player exits the starting room onto a pathway leading to the next building. From here they can look forward and see some of the level from a different angle revealing more of the collapsed building that was previously in front of them.
The player then enters a room which contains a small number of melee enemies. Upon entering the room the 3 in the player's eyesight are alerted to the player and begin to approach them.
A number of small siderooms exist in this building and within one of these rooms another enemy awaits for the player to approach.
There is also a balcony the player can move to upon which is a strong melee enemy guarding an item that the player can obtain.
From the balcony the player is also shown different views of the level and upcoming rooms and challenges they will face.
Back to the main path the player moves down towards the next building and can see a number of enemies as they approach. Nearby to where the enter the next building 2 melee enemies await them and to the right a number of ranged enemies sit atop some rubble that the player cannot climb from this side. To the right they can also see a doorway that seems to lead forward.
As the player approaches the ranged enemies they can see another doorway to their left. The player can enter either one to try and avoid damage from the ranged enemies if they are unable to deal with them with the weapons and abilities they have.
The door to the left leads to a dead end with an item in the room guarded by a ranged enemy and a melee enemy that will attempt to ambush the player as they enter the room.
The door on the opposite side leads to a balcony with some enemies and a doorway that leads to behind the rubble that the ranged enemies sit atop.
From this balcony players can look down into another building that the roof has been ripped off of. They can jump down onto the rafters of that building to skip a couple of fights and also gain an item if they manage to stay atop the rafters.
Through the door on the main path the player is able to run up to where the ranged enemies attacked them from. A melee enemy also waits near the door to engage the player as they come through.
Also in this room are a few more enemies as well as the doorway to the path forward and a doorway that leads to a shortcut the player can open.
The shortcut opens up the door in the room the player enters the level in. Now if the player dies they are able to somewhat keep their progress and enter the end of the second building.
Through the door on the main path the player walks down towards the next large building that they could see from above while on the balcony in the last building.
This building contains many enemies and the player's first introduction to the undead/grave enemies. The grave enemies fight the other enemies the player has encountered so far as well as the player themselves. Nearby the where the player enters the room is an altar where an item sits guarded by another powerful enemy. A large open door to their right indicates the path forward and on the opposite side of the altar a one way door sits ready to open a shortcut for the player.
The player then walks to a collapsed tower containing a few enemies. From here they can go directly towards the next building on the main path or take a divergent path into a collapsed area of the next building. The collapsed area contains an item the player can grab only when coming from this direction.
In the collapsed room there are a couple of grave enemies below the area that the alternate path drops the player into.
In the next room here is where the main path leads into and out of the building. There are a small number of grave enemies in the room. The path forward is indicated by the larger door which leads to the final pathway of the level.
The final pathway leads the player towards the boss room where the player must defeat the boss in order to complete the level and move forward.
There is also a path that leads to the one sided door attached to the building with the collapsed roof so the player can open up a shortcut through the level.
The boss room is a simple square layout with a couple of pillars . The boss is large enough to destroy the centre of the pillars with its attacks but the base cannot be destroyed and can be used to break line of sight to the boss.
Process
The first step for me was to sketch out a basic layout for the level on grid paper. An error I made here was to ignore the heights of the map and focussed solely on an overhead view of the map which resulted in problems in my initial blockout.
 From here I jumped into Unreal and using the Brush Tool and basic shapes made a 1 to 1 copy of the map from this overhead view.
The first blockout revealed significant flaws that I needed to address. The first thing was the height adjustments between the different buildings. In particular the building with the balcony overlapping the other room there was nowhere near enough room to extend the roof up and include rafters.
Another issue that I needed to address was my intent to use elevators in the level to keep up with the height changes. The height changes present did not necessitate the use of elevators and there was no benefit to them being included. In addition to this the area was supposed to be in a collapsed and sinking area which shouldn't have that kind of infrastructure in a functional state.
There was also the issue of sightlines and signalling of objectives to the player. From the first room the player could barely see where they were intended to go. And from the bottom they could not look back and see where they came from clearly.
The next step was to address these issues and explore some slightly different layouts. Everything fitting to the grid felt too uninteresting and again didn't help sell the idea of a collapsing or sinking city. I adjusted the rooms and built up the roofs without adjusting the paths between the rooms. The main thing I wanted to get right was the differential heights present between the buildings. In this iteration I also looked at lighting the area to get the kind of mood I was going for.
In particular note was the building which I tilted in two ways to create a more interesting area. I also liked the idea of destroyed or blown open buildings to help sell the collapse.
I dramatically increased the heights between the rooms and started to construct the alternate paths in such a way that they would connect with the main path in the ways that I intended.
The other big thing I addressed was the goal signalling or vista elements of the level to direct the player to their main goal and show them what they have gone through from the start and end of the level.
The view from the end of the level still needed work as the first building was still without a roof and thus hard to see from the boss door.
The next step now that most of the playable space found a nicer place was to construct the greater context and environment of the level. Using the terrain tool I constructed an area around the playspace.
I also looked at the connecting paths and shortcuts and tried to incorporate them in a more reasonable way to both the environment and the level itself. I tried to use the terrain as a natural barrier to keep that player within the playable areas and intended paths through the level.
After this the last steps I undertook were placing enemies, loot, and props throughout the level and building up the environment further in order to help guide the player.
The next steps from where I left the project would require testing the level in order to find the right balance for enemy placements throughout, and to find any problem areas that cause confusion or other unintended negative responses from players.