It seems that you're using an outdated browser. Some things may not work as they should (or don't work at all).
We suggest you upgrade newer and better browser like: Chrome, Firefox, Internet Explorer or Opera

I love this game. Let me tell you about the things that make it great, and about the flaws that prevent me from giving it a 5.
The basic gameplay: enter area; kill everything that spawns; proceed to checkpoint in next area. Repeat until end of level. From time to time, you'll get a boss battle. Your arsenal has some bizarrely creative primary and secondary fire combinations, like the gun that shoots shuriken and lightning.
Let's start with the good things:
This game is pretty.
Not because of the technical aspects, although it was good when it came out - but each level is a little work of art. Some are based on real-world locations. Every one is different, but they all are intricately detailed. Take a stroll through a medieval city during the plague. Welcome the soldiers coming back from World War I trenches on a railway station. Drop int an abandoned factory for a quick safety inspection. Visit the Tower of Babel for some language courses. It's like a really fast sightseeing tour, only instead of buying souvenirs you stake locals to the walls.
And then, there's the final level. Not to spoil anything, but it's a vision of hell, without so much as an ounce of fire and brimstone. Okey, maybe a little.
The enemies you meet fit well with the environments. Most games use the same models for enemeis throughout all levels. Not Painkiller - here, the baddies are reused for at most three maps. It's a game that has 10 models for a simple "run up to you and whack you" enemy.
This game has secrets.
If you're as old a gamer as me, you'll remember that shooters of old (Doom, Duke, Quake) had a bunch of fiendishly hidden areas on each level. There also was a counter that told you how many of them you had found. Sadly, this doesn't appear in modern, more story-oriented shooters. But if you remember turning a level in Quake upside down just to get that one last elusive secret, you'll feel right at home with Painkiller.
This game has freedom of movement.
Wait, did I write that right? Freedom of movement in a shooter that leads you from waypoint to waypoint, even closing all other doors so you don't stray somewhere? Well, that's all true, but I mean a specific kind of freedom. Most levels in Painkiller don't have the invisible walls that other games freely use to prevent the player from ever wandering into place he shouldn't. Here, learn a few climbing techniques and you can get to great many places. The game even encourages it. Take for example the docks level: there are a few cranes towering above it. "No way I can get up there". But after a few dozen tries, you do. You wonder if the authors thought it possible, but then you find a secret there ;)
Now, for the bad and the ugly:
The story is cringeworthy.
This fits well with the old games Painkiller is trying to be like, but at least they didn't have any painful cutscenes...
Painkiller is repetitive.
Remember when I wrote this game has a dozen of models for a simple melee enemy? Well, that's because there are hardly any bloody other types! And since they act the same, you use the same tactics over and over. This does get boring. If you played Serious Sam, you know that's it's possible to have distinct enemies in a simple shooter.
Painkiller is too easy.
You can outrun most enemies, and ammo is plenty. It's one of the only two FPS where even the highest difficulty seemed easy. Finding secrets requires ten times the dexterity of basic gameplay.
Bottom line: Try it yourself. There are demos for 3 levels out there, they are pretty representative. Love them and you'll love the full game, hate them and you'll hate it as well.