Save yourself some money by grabbing the main game AND all 3 expansion packs at the same time. It's the prudent economic choice :D (comes with linux,PC and mac builds PLUS steam key even when bought direct from us)
We often get enquiries from teachers are lecturers about using the game in education. For this purpose we make available a 'site license' for the game which allows you to install the game for up to 40 students with a single purchase. the site license cost is $99. For larger quantities please email me. To purchase the site license click the link below.