9heads Game Studios' inventive first-person puzzler Vitrum doesn't seem to have attracted a lot of attention since its quiet release last month, so its developers have decided to drum up interest in the game by making it available on a pay-what-you-want basis.

A free demo version is also available, if you need some help deciding how much you should pay. 9heads pledges to donate 10 percent of all proceeds to the Child's Play charity.