Kill 50 Chimera by detonating their heatstacks in the Single Player Campaign

Kill 100 Chimera with headshots in the Single Player Campaign

Successfully complete level 4

Upgrade all weapons in the Single Player Campaign

Successfully complete level 3

Kill 50 Chimera with Riley's axe in the Single Player Campaign

Successfully complete level 2

Upgrade both slots of a weapon in the Single Player Campaign

Kill an Executioner

Kill the Nightmare Queen

Accumulate 20,000 gold

Repair the sky