Sadly all Dev Kindlets do not work anymore on Kindle Touch with firmware 5.1. The error generated: "The item you attempted to open is incompatible with this Kindle. Please try to update your Kindle from Settings. If the problem persists, contact Kindle Customer at www.kindle.com/support
FontHack, Krosswords and Snake do this so it's safe to assume that all Dev Kindlets have this problem. (Snake was made for K3 but even if it didn't work, it used to start without errors on KT).