I doubt it's completely abandoned considering the dev constantly updates his other game and the artist is still doing promotional art for that other game, but fuck, it sure feels like it is. Most recent news was that they were updating some of the older CGs to make them more in line with the newer CGs, but as far as I know that build hasn't even dropped yet
If they really wanna work on this they should port it to something other than rpg maker. This is not an engine you make a 3d platformer in, it runs and controls like absolute ass.
Seems like there were no new updates for almost an entire year. They either work diligently and maybe even port the whole project over with lips as tightly sealed as the development process of Sliksong...or they might have abandoned it.