This is a simple implementation of the popular game Space Invaders using Python's turtle graphics library.
Use 'a' key to move the player to the left. Use 'd' key to move the player to the right. Use the spacebar to shoot at the enemy. The game is won when all enemies are defeated. The game is lost when the player is hit by an enemy's bullet.
The game's scoreboard displays the player's score and high score. The high score is stored in a text file.
To run the game, simply execute the script. The game will run in a new window.