<aside>
The first design challenge was that the player needed to be armed with weapons upon starting the game, but also needed to have his suit charged for the combat encounter at the start.
Another issue was that a scripted sequence was to be played immediately after picking up the gear, but the H.E.V. suit would constantly announce the battery level of the suit, which would play over the scripted sequence and was simply annoying.
First, I made it so that players would spawn with all weapons and several batteries on map spawn, but it was deafening to hear.
Second, I decided to let players pick up equipment themselves but this led to one playtester forgetting to pick them up.
I eventually solved these issues by only placing their weapons and ammo at the player’s position when they spawned and used an entity unique to Black Mesa called prop_hev_charger, which charges the player’s suit so long as they are within proximity. This prevents both the loud pickup sounds of the batteries and the H.E.V suit announcing the battery level.
In Black Mesa, a squad of soldiers contain squad slots, which dictate specific roles that a soldier can undertake. These squad slots only allow 2 soldiers to attack at any one time. So even though there are 15 soldiers in a squad, only 2 can attack at a time.
To increase the number of soldiers that can attack at any time, I made several squads instead, working independently of each other in the same area.
A 2nd combat design challenge is that there are times when npcs that are to be hostile to each other would not attack each other or only one side would be hostile. This was solved by using and tweaking the entity ai_relationship so that the disposition of both npcs would be to hate each other in equal amounts.
This entity is also used to control whether or not an NPC will hate or is neutral to the player depending on certain conditions, specifically for certain stealth sections.
The marine is initially neutral to the player, until the player makes combat sounds or injures the marine.
NPCs in Black Mesa are not designed with stealth in mind. Detection is immediate and often results in combat. Because of this most players will not consider them in most Black Mesa or Half Life mods.
A solution to making stealth sections however was found in a section in the chapter Surface Tension, where players can follow the advice of a guard to be stealthy in an area with soldiers.
Checking the map source file reveals how this was done.
In the map source file, several brushes acts as a barrier between the walkway and the floor below where the marines are. These brushes have the BlockLOS texture, which blocks line of sight of NPCs, but not players.
The brushes are destroyed when players make sounds that can be heard by the marines, or whenever the marines hear combat sounds.
Placing the brushes in the windows gives players a chance to observe a room without being seen.
One difficulty was communicating stealth as a viable option to players. Though imperfect, I settled on 3 design cues to help:
The first was by making it so that players are always elevated above the enemies they were going to encounter and those near the windows always had their back face to them. This enforces a realism that people tend to not look upwards.
The second was making the windows frosted or tinted, to give the impression that it would be difficult to see through them unless they were paying attention.
The third was by giving a text message telling players that the soldiers are distracted, hinting that they won’t notice the player.
A fourth way (that could not be implemented) was scripted sequences that showed enemies being distracted, rather than just standing idle.
In Black Mesa, sentry fire is considered silent to NPCs. To make it so that marines respond to a sentry firing, a destructible brush is placed around the sentry, which when destroyed, alerts the marines through an I/O system.
The yellow block is invisible to the player, and is destroyed when the sentry fires.
Here, players must head down an elevator shaft. This section serves 2 main purposes besides general gameplay, the first is that it acts as a one-way gate, and the second is to provide a story beat, which is that the facility is being overrun by organic matter from Xen.
From a story perspective, this organic portal tells the player that Xen growth has become so pervasive they are warping space in the facility and give an impression of non-Euclidean geometry. From a design perspective, it hides the lack of interconnectedness between levels (for example, suddenly going from the Black Mesa labs to Xenian facilities)
Showing immediate inaccessible spaces early helps create a space that is larger than the playable space that is immediate.
The grenades shown in a window that cannot be broken communicate to the player that there isn’t a direct way to reach them. The stairs that visibly lead down to it, followed by the breakable glass above, give a couple of hints on how to reach them.
https://youtu.be/7MIsKJywYLA?si=pxuRQ9zcK5qqQgFH
Here the player sees several items behind an inaccessible window, which helps to establish that maybe the player will eventually access them. A door with a retinal scanner at the side of this room hints at what is needed to enter.
The operating room has raised walkways to encourage vertical combat. Not only do the pillars and crates act as cover, but even the large surgery machinery hanging from the ceiling acts to break sightlines between the 2 walkways. I consider it important to factor how the environment can contribute to gameplay, rather than see environment design and level design as separate.
Vertical level design creates a larger sense of space while reusing it and gives the impression the player is traversing a complex path, rather than just going in a straight line.
Sometimes a section does not need much thought to be memorable. This warehouse is full of explosive barrels. Most players won’t even think about engaging tactically here, and instead find the nearest barrel to an enemy to blow up and watch the fireworks.