As you progress and level up in Disney Emoji Blitz, your Blitz Bonus will increase! The Blitz Bonus percentage shown under your current Mission Level is the additional amount your emojis will increase in point value during Blitz Mode.
For example: If your Blitz Bonus percentage is +200%, an emoji that's 300 points will be worth an additional 200% of its normal point value or 900 points when cleared during Blitz Mode.