Let's have a look at the case:
Minimum requirements:
Win XP or Vista
Pentium 4 2.4Ghz single CPU
1Gb RAM
Video card DX9.0c compliant, 128Mb RAM, Nvidia 6600/ATI 1300 or better.
DX9.0c compatible soundcard
8Gb disk space
Recommended system:
Win XP or Vista
Intel Dual Core 2 CPU
2Gb RAM
Video card DX9.0C compliant 512Mb RAM, Nvidia 7900GT or better
Creative X-Fi Gamer soundcard or better
8Gb disk space
As well as the gameplay being good it's the whole setting and atmosphere of the game that makes it enjoyable. All 1930's, Art Deco and plain weird.
Damn shame Bioshock 2's been delayed, I was looking forward to that