Snake Pass only removed the jump ability and perhaps became a puzzler but still has everything else from the plateformer (in my opinion). Here I don't see anything making me think about a hack and slash and wouldn't have thought it was one without the title. Snake Pass on the other hand...
But of course a game with it's main mechanic removed will transform in another genre, you're right. However I think this is the part of this jam where the theme is complicated, how to remove a mechanic without removing the essence of the genre? I think (and it engage only me ^^) that this game missed the point by removing to much from the hack'n'slash it's supposed to come from.