Use the arrow keys or the WASD keys to move. Once you reach the fifth level, you'll get a sword. If you have the sword, then when you press the spacebar, the ninja will use his sword. If you reach the fifteenth level, then you win!
You can't die! :D Thank you @VinCrafts for the idea on how to make the ninja. Here is the original project: https://scratch.mit.edu/projects/616400540/
