Difficulty Scaling tutorial - Underhell mod for Half-Life 2

When playing Half Life 2 on Hard Difficulty, the only differences you'll notice are:

1. You die more easily.
2. Enemies are harder to kill.
3. When you pick up ammo, you get less of it.

Since we don't like to turn enemies into bullet sponges, we decided to diminish the edge the enemies get on Hard difficulty, and simply to add more of them in certain areas.

More Bad Guys

Therefore, we added a couple of keyvalues and inputs to the npc_maker and npc_template_maker entities, that look a little like this:

Keyvalues

"MaxNPCCountHard"
"MaxLiveChildrenHard"

Inputs

"AddMaxChildrenHard"
"SetMaxChildrenHard"
"SetMaxLiveChildrenHard"

For everyone who knows how the NPC Makers work, this is pretty straightforward.
Basically we added Values for making NPCS that are prioritized based on the Hard difficulty.

Therefore if I were to "SetMaxChildren" to 10, and "SetMaxChildrenHard" to 20, then 20 NPCs would spawn when playing on Hard difficulty, and only 10 would spawn on Easy and Normal.
Difficulty settings are also adjustable during play, and the entities should dynamically adapt to the settings, so if you are finding one spot too hard for your particular skills, you can always lower the difficulty to your preference.
But then again, if you're playing on Hard, it's because you're a sucker for challenge, aren't you?

Less Random Loot

The second step we have taken to raise the difficulty of the game, is to lower the amount of random loot you will encounter throughout the environment.
For those of you who have read the Item_Random for random loot ! tutorial, you'll notice that the chance of an item NOT spawning is decided by the "nothing" keyvalue of the entity.

Therefore, we added a few Console VARiables, that dictate a multiplier based on difficulty.

sk_itemrandom1 0.75
sk_itemrandom2 1.00
sk_itemrandom3 1.50

This multiplier will make it so LESS (0.75) "nothing" is selected on Easy (therefore more items)
Normal amount (1.00) on Normal
And MORE (1.50) "nothing" on Hard difficulty (therefore less items)

This way, when playing on Hard, players will be required to manage their inventory more carefully, as well as their ammunition, they will be facing more foes with less resources, turning the game into a rougher survival experience.

Just remember, for most situations, fighting isn't the only option.