Shadow Fist

A stickman beat-em-up that goes up a building one floor at a time. Each room is a wave of enemies, a golden key and a door, with a boss at the top of the level, and the movement between rooms happens on ladders and in elevators rather than by walking right. Combat is a chain of presses rather than a combo list, which keeps it readable at speed. Shadow Fist is the kind of game that was everywhere in the Flash years, rebuilt properly for a browser that no longer runs them.