press space to start recording and space again to play it. Or u can just click the button. this system uses lists to store every instance of x, y and the costume at every point during the recording and the replay sprite reproduces those positions and costumes in order.
the actual "replay" code for the player sprite and replay sprite together is less than 30 blocks. this took only around an hour or two to code CONTROLS: left and right to move left and right (slow movement while holding down aswell) up to jump