I like the concept !
But yes , it's short :')
Some suggestions and observations :
- At lvl 26 explosion radius you basically need 1 bomb
- You can stack dynamite ( not a problem in itself )
- The explosions is still visible a short time in the upgrade menu , when you stack dynamite it make it unreadable a short time
- Maybe add some resistance to stone ( rarest => toughest )
- So with it , damage upgrade
- Other dynamite ? a stronger but with less radius , a digger one , a light with high radius
- Maybe add like a digging concecpt , any explosion on an other could dig and maybe discover something or unlock new world