Thank you for your nice comment. I consider to implement the following things:
- Some kind of limited wall-destruction: Maybe I could introduce another collectible item called "drill" which enables you to remove one wall element by bumping it. I think the drill must be consumed when being used. But analog to the nitros the player can collect many of them, allowing him to dig longer tunnels by investing the corresponding amount of drills.
- Support of a tileset. Maybe optional since some people could prefer the clearer ASCII-Look.
- Support of additional keysets to better allow players who are lacking a numpad to enjoy this game.
Pleas feel free to suggest other things to be considered!