Sorry about that - as I improve in game development I will make sure to watch tutorials on graphics settings menus to at least give players some more control over FPS in my future games.
Were you able to record a time? Or was it unplayable for you without a graphics card?
There's a timer at the top that counts the amount of seconds you were able to defend the turtle. For example, my best run so far is 127 seconds.
Glad you were able to at least play the game and make some lines in the sand.