Hey there :)
Yes it is. Admittedly, things are a little confusing for this game since the most current itch.io release (v0.0421) is not labeled as a demo. It's simply labeled as the latest build of the game, but appears to contain identical content to what was released as a demo on Steam.
Assuming a more feature-complete version of the game is eventually released on Steam (and/or itch.io) which contains a longer campaign (which I am expecting eventually), my plan is to at that point rename the current "Any%" category to "Any% Demo" and create a new "Any%" category for the full release. As is, I've seen no reason the itch.io "latest release" and Steam "demo" shouldn't be scored against each other, since they contain what appears to be the same content - the difference between versions however is tracked via the "Game Version" annotation.
I will make a note in the category rules to hopefully clarify this for anyone who may have the same question.
Thanks!