Textfyre’s steampunkish adventure IF The Shadow in the Cathedral is now available on the Kindle.
I haven’t played it in the current format, but it’s an entertaining and well-written piece that got less attention on release than it really deserved. Here are a few things I wrote about it at the time.
Emily Short's Interactive Storytelling 
Kindle only? I have an iPad and hate the thought of buying a Kindle-anything
For now, I believe so — unless I’m mistaken, Kindle Interactive software doesn’t run on the iPad’s Kindle reader app. But there are indications that Dave is also working on an iOS version of this, and it looks like Android as well.
Yes, when Zarf kindly finishes up the work he’s doing on the iPad, I plan to port the glulx file to his codebase and release it on the iPad. I already have an Android implementation and am working on publishing that soon. A web implementation will follow later in the year and a Metro-touch based version on Windows 8 and Surface will come out towards the end of the year (or possibly sooner if certain other things fall into place).
Shame you can’t get it in the UK!