It would appear that, sadly, the desktop version of this game just doesn't work. It says that it couldn't load a .dll, unfortunate because this could be a game that hold up today.
It's unfortunate that this game died alongside Unity, was one of my favorite games to play when I was younger. Never did beat the final level. If the dev still reads this, please port this to WebGL! This is honestly one of the best unity games on kong that hasn't yet been ported.