Tank Keeper by NuSan has been recently published for the Pico-8.
- white rocks: fuel that you must bring back to the tank
- brown rocks: upgrade your mining power
- yellow rocks: temporary boost your move speed
Your tank will only move if there is no rocks on the path and if fuel is sufficient. Use arrow keys to move your character and mine simply by repeatedly colliding with a rock. The deeper you go into the caves the harder the rocks will be, but you will find more resources.