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This was a leveldesign project I did as part of the portfoliocourse at The Game Assembly. My goal was to design a layout for a VR experience with a vertical slice to show of my ambitions for the two major settings. The project faced a lot of difficulties due to my inexperience with Source 2 and the VR-development workflow, but the level is playable from beginning to end, with some loose ends that will be specified further down.

This is a project I plan on continue working on until I have a finished level that I can release on the Steam Workshop, so this page will describe the level in its current state.


During the rebel revolt at the end of Half Life 2, a rebel soldier is tasked with taking out a Combine Overwatch Station by the foot of the Citadel. The ground has been collapsed by the Combine to make way for the construction of the Citadel, exposing the old underground sewers and maintentance tunels. Use these to get closer to your goal but beware, the underbelly of City-17 is a dangerous place.


  • Enter the Xen-infested underground tunels.

  • Find a way past the blocked gate.

  • Fight your way through the Combine base.

  • Shut down the Overwatch Station.


  • Development time: 7 weeks part time

  • Engine: Source2

  • Genre: VR/FPS


Level Design - Marcus Tegerhult

"Half Life: Alyx" and "Source2" - Game and SDK belong to Valve Software.



Overview with text detailing the flow and objectives.


Overview which details enemies and pickups

Start of the level

The level begins just after the player has found a way past the Combine barricades. The ground has collapsed due to the Combine's expansion of the Citadel and the only way forward is a risky treck along the edge of the ravine. Against the skyline, the goal can be seen.


This area is mainly for tonesetting. Central to the level is the large ravine that ends in fog far below and therefor the player gets some time to take in the setting and observe their objectives from a vantage point before finding a way to continue forward. A sewertunel that has been exposed to the outside is the only way forward.


Path the player walks along at the start, framing the final objective


The underground area is made up of underground sewer canals and maintenance tunels overrun with Xen-infestation. There are signs of a failed Combine containment attempt made, with Quarantine Foam Tanks and Combine forcefields left behind.

The first enemies of the level are barnacles and headcrabs that dig out of the ground, or stand in ambush behind corners. They serve to give the player some simple challenge as a build up.

An electric gate has been overgrown by the Xen-fauna, making the direct path forward inaccesable, the player has to walk a longer way around by breaking the lock on a door that leads to a back-corridor. Behind the chainlink fence are some Armoured Headcrabs that the player has to deal with by acctually opening the door, rather than shooting them through the fence.


The view the player sees when crawling beneath the old waterlock. They're susprised by a headcrab that digs out of the ground

The second large sewerway mirrors the first somwhat in shape but is mean as an older waterway. Here there are more headcrabs and barnacles for the player to get past, as well as an optional cache of supplies hidden behind a large amount of barnacles. Continuing into the next corridor, the way forward is blocked off, but due to the noise the player is making, a zombie busts down a cracked wall. Past the wall there are multiple zombies that the player have awaken. They have to fight their way across the think walkways while battling a few newly awoken zombies, before reaching another window they can break through, getting to an uncontaminated part of the underground tunnels, that acts as a bufferzone before the player confronts the Combines.


The second sewerway. This small area acts as the vertical slice for the "Underground"

Entering the Combine Base

The player exits out of the dark maintenance tunnels and into the sunlight. There are some combines standing guard that the player has to confront. The first Combine Soldier can be snuck up on for an easy kill, but then the three others, 2 wielding SMGs and one wielding a Shotgun, will take position and fire upon the player. This is a short battle where the player has the high ground. During the battle, Combine backup is activated and runs across the bridge to fight the player

Upon continuing forward across the bridge, the player is ambushed by multiple combines who take position and fire at the player. Being so exposed, the only real cover the player can utilize is the paneling on the side of the bridge. If the player manages to take out the Combine Commando, then a Combine Suppressor will spawn on the upper left walkway and fire upon the player.

Once it's safe for the player to continue, they climb the ladders to the top floor and use a cargo elevator to reach the Overwatch Station for the final gameplay moment of the level.


When the player walks out on the bridge they see Combine soldiers charge out on the bridge and take position. The player is left feeling exposed as their only cover is the panneling on the side of the bridge

The final battle

To end the level there's a huge gunfight that starts when the soldiers see the player ascending on the elevator.  Upon being activated, the soldiers take position and open fire once they're done. About half of the soldiers are defensive, and the other half aggressivly pushes towards the player, forcing them to bunker down for a bit before pushing forward to take out the ones who've taken vantage positions further back. The cargo on the elevator makes for good cover to hunker down on initially, but later the player can use the left-hand side to push up on the defending combine. Another suppressor has joined the fight at this point, taking position on the roof.

Once the remaining combine is defeated, the player shuts down the Overwatch Station and the level ends.



My goal with the project

My goal when I started was to get a gameplay ready layout that takes into consideration the restraints of action-gameplay in VR, and offers an engaging and balanced gameplay experience. I also wanted to have at least one area that could serve as a graphical vertical slice. However, during the course of development I encountered a lot of issues with AI and the VR-development workflow that lead to some loose ends in the layout. There's one area that ended up not being finished in this iteration, and a lot of small scripted events ended up being left unfinished as I could not figure out a lot of aspects of the Source 2 "input/output" system that most scripted events are created through. By the end, I cut a lot of these small scripted events out due to time restraints and focused on getting the baseflow of the traversal and combat to as high of a level as I could.

Designing for VR

VR is still a fairly young medium, and one that comes with a lot of interesting opportunities and potential pitfalls. While it offers a much more immersive experience, you also become more aware of your own body and what actions it can and cannot do. Designing for an action experience like Half Life: Alyx therefor required me to take into consideration how players tend to move in VR. From my own experience, I'm much more comfortable staying stationary in VR as moving a lot in combat leads to less accurate shots and makes it difficult to keep track of enemies around you. You generally wanna be able to keep your head still, so you can focus on the targets ahead of you. I took this into consideration when setting up Combine encounters with some pushing aggressivly and some offering support from further back. The dynamic that this created was having the player be able to hunker down for the first half of each fight, then being forced to take a more aggressive aproach to take out the ones staying behind.

For combat against zombies and headcrabs it was generally a bit easier to design for. The most important thing was to make sure that the player had opportunity to put distance between themselves and the zombies, so they could line up shots

Interactivity was a big part of my enjoyment of Alyx, however things like interactable props was just something I didn't really have the time to mix with. Some minor things I did that I felt was important for the gameplay loop however, was pickups in fun places, like shotgunshells you had to lasso across a hole.  For some encounters with headcrabs I also made sure there were things like chairs for the player to block jumping headcrabs with.


Referencepictures were used sparingly as finding ones that fit my vision was difficult. Instead I mainly used a few to get an idea of the mood I wanted


Once I had an idea I created a quick sketch of the level, nailing down key areas and setpieces that I felt would be important. Using the first view of the ravine I wanted the end goal to be framed so the player knew where they wanted to go, as well as to set the mood and wow the player, before they head into the more claustrophobic underground area, where there is a bigger focus on mood and exploration.

The Combine focused half of the level is where I switch to more of an action focus. While there is some combat in the underground section, I never designed it with the goal of challenging the player, but rather warming them up, as the zombies are slow and melee-based. However the Combine have more of an equal footing with the player, leading to a significant increase in the challenge the player faces.


The idea of a Combine bridge that the player had to cross in order to get to the goal was the one thing that never really changed during the concept. It was an epic setpiece that made for a pretty fun "balcony shooting" segment. However most other parts of the layout ended up getting changed around as they never quite felt right.


Original layout overview


Blocking out the base geometry in Source2 is fairly quick and painless. In the engine there is a sort of mesheditor, evolved out of their old BSP tools, that can be used to build anything from simple blockout geometry, to complex meshes. Building the first blockout was therefor a fairly quick process. In the initial blockout I was mainly just figuring out scale and trying to nail a mood for the level. I felt that the nighttime setting would make for a good "infiltration" feel, but when I got the lighting in place I felt that it didn't do the vista justice. It obscured a lot of detail and would've required a lot of lightingwork to look alright. In later itterations the time of day was set to a setting sun as it illuminated the environment better and created a more epic feeling, which I what I felt the implications of the story warranted.

The underground

Having a calustrophobic underground area that contrasted to the more grand outdoor area was something I felt would help the feel of the level. It acts as a very clear contrast to the outdoor area, both in terms of tone and gameplay elements.

My original idea for the underground was for it to be exploration heavy, with a focus on keyhunting and puzzlesolving. In the first itteration there was a locked door that needed a keycard to unlock. The player would have to journey deeper into the complex in order to find it, and upon picking it up multiple zombies would spawn, adding a twist to the backtrack. The following two itterations followed the same idea originally, however based on feedback I soon came to the conclusion that roadblocking the player and sending them on a quest to find a key so early in the level just wasn't fun. I quickly made a decision to scrap the entire keycard hunt and redesigned the explorative bit of the level into a linear detour with a focus on small combat challenges and moodbuilding.

I kept the keycard door but made it overgrown, using it to draw player towards it. I also added large windows with light flooding out of them in order to give the player more

The control room was designed with some visual storytelling in mind.


Editor screenshots. Roofs removed for ease of viewing

Combine base: Bridge

I wanted the Combine areas of the level to act as a stark contrast to the underground segment. While the underground was cramped and dark, filled with zombies and headcrabs that needed to get close to the player, the Combine areas were all bright outdoor environments with long open views and a focus on covershooting. Originally this entire segment was very linear and mostly consisted of walking through linear corridors, fighting multiple onslaughts of combines.

Originally the bridge between the underground and the Combine area was a small passage where the player got the opportunity to drop down on the combine and ambush them, before going into the fight. Later itterations kept the idea of the player sneaking up on the combine, but worked on breaking up the linear "corridor" nature of this mapsection by adding an arena consisting of a maintenance office of some sort that has been exposed to the outside due to the Combine's terraforming.

The bridge-part remained largely unchanged during the development of the level, it was mainly the surrounding areas that changed. On the bridge I wanted the player to be ambushed by combines attack from the opposite bridge, leading to a shooting segment where the player has to crouch behind the paneling on the side of the bridge for cover, leaving them with the feeling of being very exposed. This type of covershooting segment I felt worked very well in the VR-format, due to the limited movement of VR-titles. The backdrop of the sun setting made for a very epic feeling as well.


Editor screenshots

Combine base: The area that connects the bridge to the final area

This particular section of the level was the one place that ended up being left unfinished. I never quite knew what I wanted to do with it, as it couldn't really be another intense combatsegment since there were already two ones just before, but I also wanted the player to do something engaging, as just walking in Half Life Alyx can be quite dull, due to the slow walkingspeed. I had an idea of  adding a small segment where the player had to find a way past a force field by crawling through an old ventilation, that would collapse and plunge the player into the final battle. In Half-Life: Alyx, combine force fields are shut down by using your hacking tool and following a wire, so the player would follow the wire, find the ventilation and then crawl into it, thinking they're going to solve a simple hackingpuzzle, before the ventilation collapses beneath them. While the concept seemed cool, falling in VR is still a weird feeling that a lot of people dislike, and because of this, I ended up removing this completely. In the current version the player uses a cargo elevator to ascend up to the final area, rather than falling down into it. The cargo on the elevator acts as cover for the player, and the slow ascent serves the same function as the one-way vent drop, but is more comfortable for the player and contributes to building tension as the player slowly comes into view of the Combines.

In the current state of the level, this area is simply a corridor leading to the elevator.

Combine base: Final Battle

The final area of the level went through the most itterations. In the first itteration it was a warehouse the combine had repurposed to an outpost, however due to the grand surrounding area, this felt like a bit of a waste. The warehouse inspired layout never got finished, instead I started working on an outdoor itteration.

Playtesting was mainly done by just placing out combines in the positions I wanted them and disabling their walking. When I felt that the layout was fun to fight in and that the Combine's positioning was fun to fight against, was when I started working on the AI scripting, so they spawned in at the appropriate time, and ran to cover/vantage positions, to give the player a more engaging battle.


AI and scripting

As part of getting a fully functional layout I had to learn the different quirks of AI and scripting in Source 2. Since I had some experience with Source 1, I had a general idea of what I had to do, but the lack of documentation on Source 2 meant a lot had to be achieved through trial and error. Setting up AI schedules to spawn enemies and have them run to a specific position takes some time, and due to long compile times, the process of setting up AI and testing combat against them could be a long process.


Some enemies have small scripted events saved as prefabs in the SDK. For example; the zombie that busts through the wall in the underground is simply a finished prefab that all I had to do in order to get working was tie it to a trigger volume. However some prefabs weren't nearly as straight forward. On the bridge segment I wanted to use a Combine Helicopter to fly over the player and draw their attention to the combines running out on the opposite side of the bridge. However I never managed to activate the heli when experimenting on my own, and therefor I ended up having to shelf that idea for now. I decided to skip all my scripted events and simply focus on the enemyplacements and their spawns, choosing to work with scripted events that weren't important to visualising the combat and exploration further on.


There was a large amount of props and textures that I could use when propping. When blocking out some areas, like the underground, I ended up using a large amount of finished props even though it wasn't my vertical slice. My reasoning for this was that when it comes to more organic shapes, which the Xen flora is, it's quicker to just stack the meshes on eachother, rather than building representative shapes with the in-engine mesh editor. The two areas that I made into my "Vertical Slices" were the big combine fortress and one of the Xen-infested sewers, as these best represented the mood in the two different "settings" in the level.

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