With the Stamina/Sprinting system working fine, I threw together Doom 3's Adrenaline powerup, and it seems to work. Stamina count is above ammo in the bottom-right; I didn't want to throw together a hud bar for a test like this.
Since this is designed as a resource for modders, I made two versions of the Adrenaline; one that behaves like Doom 3's (infinite stamina for the duration), and one for people who don't want a stamina system that behaves like Quake 3's medkit (heals you to full when you use it).
The pickup and inventory sprites are placeholders.
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