This game is absolutely worth the price if you enjoyed the original. Ignore the other reviews, seriously. Let me break it down easily for you:
There's less levels, yes. But the included ones are EXTREMELY pretty. Everything was touched up, but not much has changed, except for a few surprises on some of the maps :)
The game is better to buy if you are going to get the dlc's, which add the other maps and a few new ones that actually live up to the painkiller style! (nazi bunker and coastal level).
They also made changes on dlc versions of other old levels, such as new areas for the Asylum and cool changes to Snowy bridge.
I REALLY enjoyed this and it was so SO satisfying to see these amazing levels in full HD. It didn't feel as nice playing painkiller in the original graphics as the years went by. It DID get dated, it's still a classic.. but Nordic Games has done a terrific job.
This was not as fun or functional on release, but after the mega-patch it's functional and FUN. You now CAN unlock tarot cards on your playthrough with your friend, so playing trauma together on a playthrough is exciting and fun, and progression can happen.
SURVIVAL: These are GREAT challenge levels brought into the game. Even for veterans. Some of the difficulties are quite hard even for good players and it's fun to see how well you can do. It's fun!
STORY: Sub-par unfortunately. It IS a (maybe?) canonical sequel, but the concept is kind of crappy and the voice-acting for Eve is bad (you can hear her microphone buzzing a tiny bit). But Painkiller doesn't need too much story!
CONCLUSION: This is a lovely game if you buy the DLC's. I dunno about Heavens Above because it's some gimmicky 3rd person mode but I imagine it might be fun too. The rest is spectacular. <3