There is a free version online https://www.newgrounds.com/portal/view/695558 or on android https://play.google.com/store/apps/details?id=com.RedForestInteractive.DeathbyNi.... We are going to a release a version for apple soon too.
We will keep the downloadable versions paid as we put a fair amount of work into the game and feel that this justifies the price and thought it would be a good way for fans to show support for our work. I hope this was helpful!!