I really enjoyed the long-form post on Parsing and alternative types of IF. It reminded me that I had an almost complete hybrid CYOA / IF system on my hard-drive. So I dusted it out and made it open source and put it online.
A trivial (two state) example is at: http://idm.me.uk/undum/tutorial.html (no loading progress bar yet, so wait until the images load).
And the code is available from: http://github.com/idmillington/undum
Although the dedicated documentation is pretty scant, the source code is very thoroughly commented (e.g.
I haven’t played with it very much yet, but I do admire the pretty presentation style in the tutorial. It appears to share some features of the Choice Of… games, such as tracking of stats and branching/rejoining story paths. What it does differently: all text from previous attempts is retained, rather than clearing the screen, so what you get is a continuous narrative. The typography is attractive, and images can be included as embellishments.
Those interested in this space should check it out.
Edited to add: the code and examples are now available from undum.com instead.