That's a great idea, it could be a "mage" turtle or something similar that could blast blocks above with a fireball. I'm adding this to my list of post-v1.0 ideas to explore. For now, I'm focused on wrapping up the core features before calling the game complete.
Multi-cell digging is definitely on the roadmap too. I'm still figuring out the best way to implement it, whether as an accessory, a special turtle, a tool, or maybe even a consumable like a bomb. Thanks again for the suggestion!