Mobility + Combat. Double jumps, wings, and harder bosses

You should be able to change direction while falling by using a second jump, because it kind of sucks because there is no way out of dying if you accidently slip. Wings and jetpacks, if they were implemented should only be a very short flight time so it doesn't take away from the original mining and collecting aspect of the game. They would be a really cool addition for combat because bosses could have attacks you actually have to dodge instead of just rapidly tapping them.