You're recommended to have a host (or two), which is (are) able to run two VirtualBox VMs with the following configuration:

Router: 32-bit, 1 core, 512 Mb RAM, 1 Gb HDD Vuln Image: 64-bit, 2 cores, 2 Gb RAM, 20 Gb HDD

You need 64-bit CPU with virtualization (VT-x or AMD-V) on host machine to run 64-bit VM.

The Test Image has the same requirements as the Vuln Image (you can shut down the Test Image when the game starts).

We recommend using Virtual Box 4.3.x or later.