You are stuck in an apartment building with endless floors. Observe your surroundings carefully to reach the 15th floor and reach the roof of the apartment building.
Don't overlook any anomalies.
You will encounter different endings depending on your level of understanding of the anomalies you will encounter on the floors.
If you find anomalies, turn back immediately. Go downstairs.
If you don't find anomalies, don't turn back. Go upstairs.
When you reach the 15th floor, 3 different doors await you. You will face different endings at these doors. If you are more careful and make fewer mistakes, you will get the best surprise ending.