Taking a mechanic out of a genre might turn the game into another genre. That's just how it works. Even Snake Pass, the game that the theme video for this jam is about, isn't really anything like the 3D-platformer genre it started out as before they removed jumping. On the official website for the game, they call it an action-puzzle game. That isn't a 3D-platformer, so is Snake Pass disqualified from its own jam?
Viewing post in Path of Pacifism jam comments
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.