1. Event Challenge : First, you need to complete the Event Relics and Event Focus levels, as well as the Elite Station on the far right.
2. Path planning : Pay attention to the dynamically changing grids in the map. Every move will consume part of the area, so you must make a strategic layout in advance.
3. Random drops : Each time you clear these levels, you will receive random medals, so luck and strategy are both important.
4. Goal setting : In order to pass the ticket inspector, you need to accumulate at least 5 skeleton stamps, which is the key threshold.
5. Increasing difficulty : As you clear more levels, the difficulty of subsequent challenges will gradually increase to ensure that your character level keeps pace.
6. Skeleton stamp submission : After you collect all 5 skeleton stamps, go to the ticket inspector to deliver them. After this step is completed, you can successfully pass through the mysterious door behind the ticket inspector.
Through the above steps, you can successfully open the door in "Zero" and enjoy more content of the game. Wish you good luck on your journey of discovery!