Cute little game. The visuals look great, but no matter how I tried, I couldn't find a way how to multitask making two swords at the same time. Other than that the game is nice, no bugs and the mechanic is clear.
Try putting a second iron ore in the furnace as soon as you remove the first. This way, it should be ready to pick up as soon as you finish the first sword, allowing you to continue the loop without stopping.
