Gotta love that classic arcade game! While it's missing some music and some sounds and has a few bugs because you ran out of time, you could build upon this. May I perhaps suggest a few ideas? :) You don't have to use any of them, these are just some thoughts.
- You could add a tween to the snake movement so it moves smoothly between each square.
- You could add a unique twist to the game to make it more original. Perhaps the apple is moving around, or there are power-ups or something.
If you don't use these ideas that's fine. This game has quite a lot of potential if you're willing to keep it going after the jam. Nice job with the game! :)