Hi there, I know that many of you know about this mods, which add some changes, features and mainly bug fixes into Painkiller games, it is a must have for PK games, mainly for Overdose, I know OD is not here on GOG, but just in case I am posting it too.

Painkiller Powermad 3.62

Bug Fixes:

• Startup videos are disabled
• Integrated Colloseum tarot card fix — fixed in 1.61/1.62 => removed in Powermad3.62 +
• Integrated Ruins ammo box fix (thanks dooguesgoober4)
• Integrated Abandonded factory destroyable objects fix (thanks dooguesgoober4)
• Integrated Loony Park hidden fireworks sack fix
• Integrated Stone Pit missing two chest at the beginning fix
• Integrated Stone Pit out of level holy item fix (thanks Crazy)
• Integrated Stone Pit holy item (statue) placement improvement
• Integrated HUD showing only three digits of health fix (thanks Dayve)
• Integrated Level statistics fix
• Integrated language fix (switching languages through the config file works)

http://pkzone.org/downloads/powermad-3-62/

Powermad: Painkiller Overdose

Bug Fixes:

Version 1.3:

• General fix for objects falling out of the level/into water not being counted as destroyed.
• Fixed monster counter in Ragnarok.
• Fixed monster counter in Dead Marsh.
• Fixed misplaced ammo box in Riot.
• Fixed last bunch of barrels in Ragnarok benchmark blowing off early sometimes.

Version 1.2:

• General fix for objects falling out of the level/into water not being counted as destroyed.
• Fixed the weapons-destroyable-objects bug.
• Fixed missing destroyable objects in Ragnarok.
• Fixed missing destroyable objects in Field Ambulance.
• Fixed missing destroyable objects in Loony Park.
• Fixed missing destroyable objects in Animal Farm.
• Fixed missing destroyable objects in Nuclear Plant.
• Fixed missing destroyable object in Village of the Damned.
• Fixed missing destroyable object in Riot.
• Fixed missing destroyable object in Air Combat.
• Fixed missing destroyable object in Studios.
• Fixed missing destroyable object in Dead Marsh.
• Fixed destroyable objects counter glitch in Studios.
• Fixed three missing ammo boxes in Riot.
• Fixed two misplaced ammo boxes in Riot.
• Fixed misplaced/floating objects in Asteroids.
• Fixed wrong startup health in Animal Farm (according to MW).
• Fixed wrong startup health in Ragnarok (according to MW).
• Fixed Secret 3 in Nuclear Plant.
• Fixed not working Assault tarot card.
• Fixed downgrading of level statistics.
• Fixed monster counter in Studios.
• Fixed monster counter in Sammael’s Lair.
• Fixed monster counter in Field Ambulance.
• Fixed monster counter in Village of the Damned.
• Fixed monster counter in Nuclear Plant.
• Fixed monster counter in Haunted Valley.
• Fixed monster counter in Ragnarok.
• Fixed monster counter in Animal Farm.
• Fixed monster counter in Asteroids.
• Fixed monster counter in Desert.
• Fixed monster counter in Loony Park.
• Fixed monster counter in Riot.
• Fixed monster counter in Air Combat.
• Fixed monster counter in Dead Marsh.
• Fixed monster counter in Japan Massacre.

Other Fixes and features:

• Startup videos are disabled
• Backtracking in Japanese Massacre after finishing the level.
• Backtracking in Loony Park after finishing the level.
• Backtracking in Nuclear Plant after finishing the level
• Backtracking in Riot after finishing the level.
• Backtracking in Asteroids after finishing the level.
• Backtracking in Air Combat after finishing the level.
• Improved loading times up to 50% (hack by Goran).

http://pkzone.org/downloads/powermad-overdose/

More infos about this mods/patches and how to install or cofigure them on the site in links.

Hope this helps.