Nice little game! I had some ideas to improve the scoring:
- Link the scoring to the difficulty, so harder difficulties the score grows more quickly.
- When you 'win' a game (when all the snakes destroy themselves), the player receives a bonus say 3,000, 5,000 or 10,000, depending on difficulty.
Also, I had an idea for a different game mode: The game starts with a single AI snake and a piece of food spawned in a random position. Before the snake gets the food, the player must select the position that the next piece of food will spawn at with the mouse. When the snake gets the current piece of food, a new piece is spawned at that position. If the player fails to select a position before the snake gets the current piece, they loose. The player wins by trapping the snake so it collides with itself. This might also work with multiple snakes.
You could even have menu that lets you choose to 'Be the snake!', 'Be the food!' or 'Be the feeder!' 😂