A fun little minigame. The anvils serving as upgrades is both a creative interpretation of the special object and a great addition to the game, helping to keep it from becoming stale. With some refinement of the controls and some additional content (more maps, more power-ups, etc.), I could see this being turned into a full game.
I would only suggest adding a skip / restart option once you die, since it's not all that fun watching three NPCs play the game for me.