In Stage mode the player plays against time. There are usually 5 types of Tsum Tsum in the field in this mode. The amount of points you get per Tsum is determined by the Score stat. The goal is to gather as much points as you can, though most Stage missions have additional goals that have to be satisfied to count.
The game field in Stage mode.
The Stage goals. The uppermost bar is the number of Points, then the Star bar (you will get Stars as it fills up), then the mission goal and how much of it is completed (if you fail to achieve the goal, you'll fail the mission regardless of your Points), and then the number of Coins collected during the game;
Your Skill and Special (SP) buttons. They have small bars around them that fill up when you pop Leader Tsum Tsums. When one of the bars is fully filled, you can cast the skill by tapping on the button;
Pause button. Press it when you need to take a break in the middle of the mission, press resume to continue;
Mega charge bar. Fills up when popping Tsums, starts Mega Charge when full.
Board tilt button. Tap repeatedly to shake the game field, hopefully rearranging the Tsums into a more opportune configuration.
There are three levels of perfection for beating a Stage mission:
A single star
— for simply satisfying the mission's goals.
— for satisfying the mission's goals as well as the goal it defines as the two-star condition (usually exceeding a certain number of Points)
— for satisfying the mission's goals as well as the goal it defines as the perfect three-star condition (usually exceeding a certain number of Points)
The Stars are an important resource, because collecting a certain number of Stars unlocks extra (EX) missions on various Stages. Also, you get yellow ISO-8 crystals every time you get a new Star you hadn't had previously.
EX missions have the same base mechanics as regular ones, except you get silver Stars instead of gold ones. For each silver Star you get white ISO-8 crystals.
Finally, it is important to note, that every Stage has at least some missions that include defeating an opponent. Those are played in Battle mode.
The different stages within the game will be familiar to Marvel fans as they are locations from both the comics and MCU. They look like planets hanging on strings from the top of the screen. Each stage has a certain number of missions that must be completed before the user can advance to the next Stage. Most stages have additional extra (EX) missions as well.