interesting concept
Maybe add a shop ( each collected block is 1 coin ) where you could buy :
- mining speed
- move speed
- more life
- ....
Add a xp system that unlock abilities ( like remove a bomb if you activate it )
Add sub zone , the deeper you go the harder it explode or the longer it take to break block
So if there is sub zone , add a map
Add a signalling system ( for signal bomb )
If sub zone , then other block then a crafting system ( like fast road or even portal )
A way to heal