You've already heard about the original Painkiller's atmospheric maps, music, and fast-placed singleplayer.
But I don't seem to find any multiplayer review of this game on GOG.
So here it is: it may be dead for now but at the time it was gold. This game was even played at Cyberathlete Professional League (CPL) championships. Its movement and gameplay was somewhat close to Quake World (Quake 1 official multiplayer) but was even faster.
You could bunnyhop everywhere like crazy without stopping (there were some techniques), climb some walls by multijumps, rocketjump, grenadejump - these features were absent or highly reduced in Singlepalyer and that's unfortunate.
It had People Can Fly mod that is somewhat close to Quake Rocker Arena mod.
Almost all weapons have combos, when you combine left and right mouse click. The most important in the multiplayer was a grenade stake when you shoot a grenade upwards and try to hit it with the stake. You can even do this trick with the enemy's grenade and turn it back right into his face with the stake. Also, when at large distance, stake can shoot fire stakes that deal increased damage and can tear apart an enemy with a single shoot.
There was a must have muliplayer mod PK++ with additional multiplayer maps like famous DM_1v1_meatless and some CPL maps.
I've spent hours playing its multiplayer trying to control maps' items. I remember game legend players like sk1p, Zwiastun, AndySYS. Guys even organized events like Painkiller Black Night Marathons when you should play several hours straight. It was a really fun time. And also I remember when the game started to loose its playerbase and the last nail to its coffin was turning off Gamespy servers. However, you could still play on some dedicated servers if you knew their direct IPs. I'm not sure if there are any nowadays but I guess you can start a server and play it with friends.
Search for Painkiller Black edition multiplayer footage on Youtube and you won't regret it.
