Feedback for NodeJs Socket.io game

This is my first NodeJs project with socket.io and I've spent a good deal of time working solo. I'd like to get some fresh eyes on it. Any feedback, whether typos or design questions, are welcome!

wasd or arrow keys to move. If no one else is on, add a bot or two.

Live Demo: https://node-multiplayer-snake.herokuapp.com/

Code: https://github.com/simondiep/node-multiplayer-snake