The message clarifies that "although the demo had been finished and was ready to go," Comcept decided to switch distribution methods, a change that necessitated extra time to ready the build for release.
Comcept is retooling the demo build to deliver through the Humble Bundle store. This is a result of "feedback about preferring to have a demo that is not time-limited" and is DRM-free.
The developer meant for the demo to satiate frustrated backers after the game's launch date was pushed back from Sept. 15 to sometime in 2016. It was to be exclusively made available via Steam to contributors for a limited amount of time.
While Comcept has provided donors with clarification on the delay, it still has not given them a sense of when they can hope to play the demo. The email does offer an apology from the developer, which swears to "keep our backers up-to-date regarding the release of this demo as soon as we have more information."
The team led by ex-Capcom designer Keiji Infaune first announced the delay as an aside in an update to the game's news page. The developer chalked this up to "distribution issues," offering no further explanation.