Yes, it is still being worked on. The majority of the developer's updates are posted on their Patreon, Tumbler, and X (Twitter) pages. The latest demos are available for download, specifically on Patreon, if you pledge $12 a month.
Viewing post in Something's Wrong with Sunny Day Jack comments
I tried the free demo available on Patreon and was deeply disappointed. I was hoping what they had here was still going to be worked on. The demo on Patreon was not even half as long and the character designs have changed for the worse. I can’t afford to back every single patreon, so I guess I’ll just have to wait and see if they ever actually finish the game.