itch.io

A game that has some of or all of the mechanics: Limited interaction or the ability to be played without interaction, rapid growth - often exponential, prestige mechanic(s), An end goal/mission or a general goal of getting a higher amount of currency, and a system of buying and upgrading buildings, units, or similar.

Only requires a single button (commonly the left mouse button or a single key on the keyboard) to operate the game's controls or interact with it.