Battle out of Hell is a flawed expansion that fails to deliver what it's predecessor did.
The gameplay is practically unchanged from its predecessor. The goal is still to run around, shoot everything in sight, and then proceed to the next area to do the same thing. There were only 5 guns in Painkiller and this expansion only creates, I believe, 2 more guns, both of which really aren't all that impressive, but still effective. The gameplay is still intact and still very fun. It seems like mindless shooting will never get old. But this time around, the gameplay is hampered by incredibly stupid jumping segments. I've heard a lot of complaining about this area of the game and I didn't think much of it, but now I know what they mean. They are incredibly difficult to do so you will die a lot when attempting these ridiculous areas, which means you'll be staring at the loading screen a lot. Another thing to mention in the gameplay is the difficulty. The expansion is considerably harder than Painkiller. This game will truly test your skills and see how much you learned from playing the original.
The graphics are about as good as the last game. The levels and enemies are still very good looking. The first level is in an orphanage and it looks great and it is very creepy. The second level is a demonic amusement park and also is very well done. After this though, the levels are just as uncreative and cliché as any other FPS game, but still good enough to keep you playing. The cutscenes also look about as good as the first game. There's nothing here that will astonish you, but nothing that should make you feel like they should have tried harder.
The sound doesn't seem quite up to par with its predecessor. The guns haven't changed at all and the fact that they sound weaker than they should is very evident. The demonic sounds and laughs from the first game are also almost completely absent. It's a shame since that was a shining area. Also, there are only two cutscenes, one at the beginning and one at the end, and neither of them have an awful lot of dialogue, so it seems that the voice actors just did it real quick for the paycheck.
Overall, if you played and liked Painkiller, there's no reason for you not to enjoy Battle out of Hell. It's practically more of the same, but at the same time considerably worse. The gameplay is still intact, but dampened by needless jumping areas. Everything else is either up to par or slightly under the first game. The bottom line is this: Battle out of Hell will amaze you for the first two levels, but after that disappoint. If you enjoyed Painkiller, I can whole heartedly recommend Battle out of Hell, but don't expect it to be nearly as good as the first.