I played this for a while and have some feedback.
- I can't see far ahead when moving up or down. The camera should zoom out when moving up or down, so the player can see more than 2 tiles ahead.
- There is no need for breaking walls yet. There aren't many connected walls generated. One way to have a need to break walls could be, placing some kind of prize surrounded by walls. Maybe some kind of mini-labyrinths with a prize.
- Last idea, You could let the game begin like the classic Snake game in a small rectangle area surrounded by walls. Then the player would break the wall to reach a larger area, which is surrounded by a larger wall, and so on... and so on...
The larger walls could get even thicker, so the player really needs to break the walls, before the snake gets too big for the surrounded area.