Aside from different HEV Suit’s Armor functionality, devs missed another thing: difficulties work differently in HL1 and HL2.
In HL1, skill.cfg specifies exact values for every difficulty. For instance:
Enemy MP5 bullets do 3 damage on Easy, 4 damage on Medium and 5 damage on Hard.
In HL2, skill.cfg lists just base values used by Normal difficulty, while Easy and Hard scale some of these values (enemy health and damage received by player). To be more precise, on Easy all damage received by player is reduced by 50% and enemy health is reduced by 33%. On Hard, it’s vice versa. So let’s take this line from BMS skill.cfg:
This makes NPC’s 9mm bullets (Glock and MP5) do 4 damage on Normal and, due to how Source engine scale, 2 damage on Easy and 6 damage on Hard.
So my question is: is it possible to replicate HL1 difficulty system? Or is HL2 difficulty system hardcoded into Source engine?