This is a real Doom playthrough recorded by Wax. It preserved the game state and every input, so you can rewind it, inspect what happened and replay the same history through code that did not exist when it was recorded.
Click the canvas to lock your mouse, then move with WASD or the arrow keys and look with the mouse. Ctrl to fire, Space to open or use, Shift to walk. Esc releases the pointer.
Desktop only: this demo needs a keyboard and mouse.