Use your arrow keys to move up,down,left and right. When you turn into the fire version use the spacebar to throw fireballs. If you stand in front of the goomba you will turn small and you can also jump on the goomba to kill it. If you get hit by the goomba 2 times you will die.
This is my prototype so it might have some glitches. Sorry for the bad quality I tried my best. Theres not alot of stuff to do. Click here for the finished game https://scratch.mit.edu/projects/1142648866