Build up your units to collect gold that you can use to buy more units. This idle game has 8 unit types, upgrades for each, and achievements at certain intervals. Later in the game you'll start collecting soul orbs that give you a permanent gold boost when you reset. Gold is also generated offline so you don't need to keep the game open while you wait. You can play with just the mouse but there are also keyboard shortcuts: U for upgrades, A for achievements, X for exiting a menu, and R for resetting and gaining soul orbs.