click the a button or just click a for melted gold upgrade 1 is for gold and upgrade 2 could be bought with 150 gold or 15k melted gold to buy iron upgrade u need 3k iron click t to reset timer 3rd upgrade is 35k melted gold 4th upgrade costs 500k
3rd update added upgrade 6(wip) and added upgrade stacks and increased the prices for some upgrades
