I'm so sorry this response is absurdly late, but to be clear, we DO update the demo here on itch.io whenever there are overhauls, and we intend to continue that trend. That's why we released this 2023 demo in the first place; it had the same content as the previous public demo, but that's when we overhauled the gameplay to support 360 degree aiming, so we put out a public demo update around the same time so everyone could enjoy the reworked gameplay and have an up-to-date idea of what to expect from the Patreon demos.
Development on the game has been very slow, and it's been a while since we released a new playable build on Patreon. All of the updates/overhauls you're referring to have not been released to ANYONE yet, Patreon or not - they're all in-progress things coming in future updates. Once we get to a point where there's enough changes that are actually relevant to the public demo, then we'll update this demo like always.