The game will probably run well on even lower specifications, however below minimum specs are confirmed to run the game decently well.
If you have a Linux machine, you will need to manually install mono and might be required to do some manual configuring to make it run. There is currently no official OS X support yet, but I will work on that if enough people request it :-)
If you have lag issues, make you have the latest version of your graphics card drivers. In the case of Radeon HD7800 HD series graphics cards, a reinstall of the drivers might help as well.
Operating System Windows 7 or newer, 32 bit CPU Most dual core systems, e.g. AMD E1-2500 APU @1.4 Ghz or Intel Core2 Duo P7500 @ 1.6 Ghz Memory 3 GB RAM Hard Drive 300 MB free HDD space Graphics AMD or Intel Integrated Graphics, OpenGL 3.3 or newer Network Internet Connection required when starting the game for the first time
Operating System Windows 7 or newer, 64 bit CPU Core i7 with 2 Cores or equivalent Memory 4 GB RAM Hard Drive 300 MB free SSD space Graphics Geforce GT 650M, 2 GB dedicated or shared video memory, OpenGL 3.3 or newer Network Internet Connection required when starting the game for the first time