In terms of game file size, you will need at least 500 MB of free disk space available. The cheapest graphics card you can play it on is an NVIDIA GeForce 6100. An Intel Pentium 4 2.00GHz CPU is required at a minimum to run 18+. 18+ system requirements state that you will need at least 512 MB of RAM.
18+ will run on PC system with Windows XP and up and upwards. Additionally it has a Linux version.
