i tried to play the game, but an error popped up, saying something along the lines of:
'Traceback (most recent call last):
File "DOS.py", line 24, in <module>
pygame.error: WASAPI can't initialize audio client: The handle is invalid.'
i'm not an expert in Pygame, but judging by your source code, the problem must be with Pygame's mixer module.
downloading the source code and running it using my version of Python along with Pygame didn't really seem to be a problem though, which is how I was able to play the game in the end. i got a score of around 50. to be honest, for a game made in Pygame, it's not bad :D