You should die if the head doubles back onto the body or running into the screen border. I will look into it if you share your config (emulator, hardware, etc.) and controls (keyboard or joystick),
Thanks for downloading and leaving a comment,
Chris
I played it on an original C64 with joystick.
To me it seems like the problem occurs when I'm trying to do a U-Turn too quickly: For example, when the snake goes left and I press down and then immediately press right, before the snakes head has moved down, the snake dies. My guess is that the head tries to go right from its current position and crashes into the body behind him.