Great offline game and Potato phone friendly

Simple enough game, need to level up and pick up some gears. Take a pick to upgrade as you progress more enemies will come to kill you and you have some weapon in your arsenal to fend them off. The good side about this is that it is an offline game, so whenever you go you can play this and it will sync to the server on what you progress thus far. Great game for me, definitely be playing it for a while.