3-tsu no Hako no Heya Kara no Dasshutsu (3つの箱の部屋からの脱出, Escape From the Room With the Three Boxes) is a Flash game by Yomino Kagura and one of many from him of the escape room subgenre. As the name implies, you are trapped in a room with three checkered boxes. These boxes possibly contain a key or clues that can help you obtain a key that can get you out of the room. However, to open those boxes, you need to figure out codes and other puzzles using the other objects placed around the room.
Rxser demonstrates forethought in this run and cracks every code and puzzle as fast as possible to get the key needed to leave the room.