It promised to be a homage to classical shooters that all grew up from the first Quake, without any stupid story (but it has one, and oh God, I needed to take painkillers to live through it). It fullfils its promises only partially, and in aspects that weren't really that crucial. Yes, gunplay is nice. The variety of ways to kill your enemies and the fact that an every weapon in the game feels so really good, would be awesome, if it was indeed a classical shooter through and through.
But it is not, because it misses the most crucial element needed from this type of gaming. Level design. Oh God, what an awful levels this game has. Levels, that you want to play the shit out of flash My Little Pony web-browser game, only to make levels in this game to stop popping out and destroying the perfect gunplay.
Even with the best mechanics around, shooting can quickly get boring. And that's exactly the case with Painkiller. All levels are so dull and random, it almost boils my mind trying to understand why is this game considered a classic. I played it back in 2005 for the first time, and didn't make through the first act, I got bored so much (I returned to play the shit out of UT 2k and 2k4). All levels consist basically from a set of areas, that don't even offer a way to bunny-hop your way through. It forces you to run in circles shooting the same enemies over and over. Until the game lets you proceed to the next area. Only an old monastery level breaks out of this pattern, but it's destroyed because of the game-breaking bug that makes ending this level impossible. Go, replay it, because we fucked up our job.
This game feels like a tech demo for the physics engine, that eventually got wrapped up as a full-release with an interesting atmosphere set up, that got destroyed by the fact the game mostly consists of a barf-bowl levels, that doesn't have anything in common. You play in a cementary, just to be thrown onto... a snowy bridge somewhere else, fighting ninjas. What?